Identify the fluff that I have found in tea

Identify the fluff that I have found in tea

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I have just opened a new pack of a black Pu'er tea that I've bought at the local store selling it by weight, and found a piece of fluff in there. To me it looks much like some kind of a bird fluff. It might also actually be a plant fluff, but somehow I doubt it. Probably it was white originally, but being so long in contact with the tea made it a bit browner.

Of course it spoiled all the impression of the tea. Now I wonder if I should drink it, or even keep buying at the same store. The worst thing is that their supplier is one of the major suppliers of Chinese tea in our country, and this is not the first time I find something hairy in it. The last time it was a human hair.

The questions:

  1. Please help identify what it is (I don't mean a particular species of whatever it is, but at least what is it? Bird fluff, plant fluff, synthetic fluff?)

  2. Would you still drink your tea if you'd find such things in it? Like, should it be safe, or is there any risk in contracting some terrible infection or a virus in case if it comes from a bird?

Here are some photos that I've made:

It also very much looks like this picture I've found in the internet, but failed to find a proper description of what is it actually (the most bold one was that its a swan fluff, but I can't imagine how a swan would come in contact with the tea):

It's kind of hard to tell from the picture, but maybe it's a variety of Milkweed seed-pod that got into the tea?

How to Grow Tea Plant (Camellia Sinensis)

Almost every tea enjoyed comes from a specific species of plant known as the camellia sinensis. There are two varieties of this plant that each yield different types of teas, with specific characteristics that define each one. Black tea (called "red tea" in China because of the color of the brew) is the strongest-tasting variety due to its oxidation time in processing. Oolong tea, known for its flowery notes, is less oxidized. Green tea, the mildest variety, does not undergo oxidation at all and is pan-fried in processing to prevent oxidation from occurring.

Camellia sinensis (or tea plant) is a fast-growing shrub used to make most traditional caffeinated teas, including black tea, white tea, oolong tea, and green tea. This plant originated near the southwest region of China as an evergreen forest shrub. The leaves are glossy green with serrated edges and are similar in both shape and size to a bay leaf. Tea plant does best when planted after the last frost, in well-draining, sandy soil, and shouldn't be harvested until it's three years old.

As the story goes, tea plant was first stumbled upon by accident in 2737 B.C. The emperor at the time was boiling water in his garden when a leaf from the overhanging camellia sinensis tree drifted into his pot. The combination yielded a drink that compelled him to research the tree further, uncovering both medicinal and palatable properties.

Botanical Name Camellia Sinensis
Common Name Tea Plant
Plant Type Evergreen shrub
Mature Size 3-7 ft. tall
Sun Exposure Partial shade
Soil Type Well drained, sandy
Soil pH 5.5-6.5
Bloom Time October-December
Flower Color White
Hardiness Zones 6-9 (USDA)
Native Area China
Toxicity Non-toxic to humans and animals

Loose-Fill Insulation

If your attic or wall insulation is in batt or blanket form, whether it's fiberglass, cellulose, or another material, you generally don't have to be concerned about asbestos.

The types of insulation that were most commonly made with asbestos are loose-fill, also called blown-in, insulation. Loose-fill insulation comes in a variety of materials. It is easy to identify by its loose, lumpy form and fluffy or granular texture. Loose-fill never has paper or other types of backing, like some (but not all) batt and blanket insulation does.

If you determine that your attic or walls have loose-fill insulation, the next step is to determine what type of material it is, as only some types may contain asbestos.


Coloration Edit

In flowers, the coloration that is provided by anthocyanin accumulation may attract a wide variety of animal pollinators, while in fruits, the same coloration may aid in seed dispersal by attracting herbivorous animals to the potentially-edible fruits bearing these red, blue, or purple colors.

Plant physiology Edit

Anthocyanins may have a protective role in plants against extreme temperatures. [7] [8] Tomato plants protect against cold stress with anthocyanins countering reactive oxygen species, leading to a lower rate of cell death in leaves. [7]

Light absorbance Edit

The absorbance pattern responsible for the red color of anthocyanins may be complementary to that of green chlorophyll in photosynthetically-active tissues such as young Quercus coccifera leaves. It may protect the leaves from attacks by herbivores that may be attracted by green color. [9]

Anthocyanins are found in the cell vacuole, mostly in flowers and fruits, but also in leaves, stems, and roots. In these parts, they are found predominantly in outer cell layers such as the epidermis and peripheral mesophyll cells.

Most frequently occurring in nature are the glycosides of cyanidin, delphinidin, malvidin, pelargonidin, peonidin, and petunidin. Roughly 2% of all hydrocarbons fixed in photosynthesis are converted into flavonoids and their derivatives, such as the anthocyanins. Not all land plants contain anthocyanin in the Caryophyllales (including cactus, beets, and amaranth), they are replaced by betalains. Anthocyanins and betalains have never been found in the same plant. [10] [11]

Sometimes bred purposely for high anthocyanin quantities, ornamental plants such as sweet peppers may have unusual culinary and aesthetic appeal. [12]

In flowers Edit

Anthocyanins occur in the flowers of many plants, such as the blue poppies of some Meconopsis species and cultivars. [13] Anthocyanins have also been found in various tulip flowers, such as Tulipa gesneriana, Tulipa fosteriana and Tulipa eichleri. [14]

In food Edit

Plants rich in anthocyanins are Vaccinium species, such as blueberry, cranberry, and bilberry Rubus berries, including black raspberry, red raspberry, and blackberry blackcurrant, cherry, eggplant (aubergine) peel, black rice, ube, Okinawan sweet potato, Concord grape, muscadine grape, red cabbage, and violet petals. Red-fleshed peaches and apples contain anthocyanins. [29] [30] [31] [32] Anthocyanins are less abundant in banana, asparagus, pea, fennel, pear, and potato, and may be totally absent in certain cultivars of green gooseberries. [16]

The highest recorded amount appears to be specifically in the seed coat of black soybean (Glycine max L. Merr.) containing approximately 2 g per 100 g, [33] in purple corn kernels and husks, and in the skins and pulp of black chokeberry (Aronia melanocarpa L.) (see table). Due to critical differences in sample origin, preparation, and extraction methods determining anthocyanin content, [34] [35] the values presented in the adjoining table are not directly comparable.

Nature, traditional agriculture methods, and plant breeding have produced various uncommon crops containing anthocyanins, including blue- or red-flesh potatoes and purple or red broccoli, cabbage, cauliflower, carrots, and corn. Garden tomatoes have been subjected to a breeding program using introgression lines of genetically modified organisms (but not incorporating them in the final purple tomato) to define the genetic basis of purple coloration in wild species that originally were from Chile and the Galapagos Islands. [36] The variety known as "Indigo Rose" became available commercially to the agricultural industry and home gardeners in 2012. [36] Investing tomatoes with high anthocyanin content doubles their shelf-life and inhibits growth of a post-harvest mold pathogen, Botrytis cinerea. [37]

Some tomatoes also have been modified genetically with transcription factors from snapdragons to produce high levels of anthocyanins in the fruits. [38] Anthocyanins also may be found in naturally ripened olives, [39] [40] and are partly responsible for the red and purple colors of some olives. [39]

In leaves of plant foods Edit

Content of anthocyanins in the leaves of colorful plant foods such as purple corn, blueberries, or lingonberries, is about ten times higher than in the edible kernels or fruit. [26] [41]

The color spectrum of grape berry leaves may be analysed to evaluate the amount of anthocyanins. Fruit maturity, quality, and harvest time may be evaluated on the basis of the spectrum analysis. [42]

Autumn leaf color Edit

The reds, purples, and their blended combinations responsible for autumn foliage are derived from anthocyanins. Unlike carotenoids, anthocyanins are not present in the leaf throughout the growing season, but are produced actively, toward the end of summer. [2] They develop in late summer in the sap of leaf cells, resulting from complex interactions of factors inside and outside the plant. Their formation depends on the breakdown of sugars in the presence of light as the level of phosphate in the leaf is reduced. [1] Orange leaves in autumn result from a combination of anthocyanins and carotenoids.

Anthocyanins are present in approximately 10% of tree species in temperate regions, although in certain areas such as New England,up to 70% of tree species may produce anthocyanins. [2]

Anthocyanins are approved for use as food colorants in the European Union, Australia, and New Zealand, having colorant code E163. [43] [44] In 2013, a panel of scientific experts for the European Food Safety Authority concluded that anthocyanins from various fruits and vegetables have been insufficiently characterized by safety and toxicology studies to approve their use as food additives. [4] Extending from a safe history of using red grape skin extract and blackcurrant extracts to color foods produced in Europe, the panel concluded that these extract sources were exceptions to the ruling and were sufficiently shown to be safe. [4]

Anthocyanin extracts are not specifically listed among approved color additives for foods in the United States however, grape juice, red grape skin and many fruit and vegetable juices, which are approved for use as colorants, are rich in naturally occurring anthocyanins. [45] No anthocyanin sources are included among approved colorants for drugs or cosmetics. [46]

Although anthocyanins have been shown to have antioxidant properties in vitro, [47] there is no evidence for antioxidant effects in humans after consuming foods rich in anthocyanins. [5] [48] [49] Unlike controlled test-tube conditions, the fate of anthocyanins in vivo shows they are poorly-conserved (less than 5%), with most of what is absorbed existing as chemically-modified metabolites that are excreted rapidly. [50] The increase in antioxidant capacity of blood seen after the consumption of anthocyanin-rich foods may not be caused directly by the anthocyanins in the food, but instead, by increased uric acid levels derived from metabolizing flavonoids (anthocyanin parent compounds) in the food. [50] It is possible that metabolites of ingested anthocyanins are reabsorbed in the gastrointestinal tract from where they may enter the blood for systemic distribution and have effects as smaller molecules. [50]

In a 2010 review of scientific evidence concerning the possible health benefits of eating foods claimed to have "antioxidant properties" due to anthocyanins, the European Food Safety Authority concluded that 1) there was no basis for a beneficial antioxidant effect from dietary anthocyanins in humans, 2) there was no evidence of a cause and effect relationship between the consumption of anthocyanin-rich foods and protection of DNA, proteins and lipids from oxidative damage, and 3) there was no evidence generally for consumption of anthocyanin-rich foods having any "antioxidant", "anti-cancer", "anti-aging", or "healthy aging" effects. [5] following this 2010 review [ citation needed ] , there does not seems to have any substantial clinical trials indicating that dietary anthocyanins have any beneficial physiological effect in humans or lower the risk of any human diseases. [5] [6]

Flavylium cation derivatives Edit

Selected anthocyanidins and their substitutions
Basic structure Anthocyanidin R3 R4 R5 R3 R5 R6 R7
Aurantinidin −H −OH −H −OH −OH −OH −OH
Cyanidin −OH −OH −H −OH −OH −H −OH
Delphinidin −OH −OH −OH −OH −OH −H −OH
Europinidin − OCH
−H −OH
Pelargonidin −H −OH −H −OH −OH −H −OH
Malvidin − OCH
−OH −OH −H −OH
Peonidin − OCH
−OH −H −OH −OH −H −OH
Petunidin −OH −OH − OCH
−OH −OH −H −OH
Rosinidin − OCH
−OH −H −OH −OH −H − OCH

Glycosides of anthocyanidins Edit

The anthocyanins, anthocyanidins with sugar group(s), are mostly 3-glucosides of the anthocyanidins. The anthocyanins are subdivided into the sugar-free anthocyanidin aglycones and the anthocyanin glycosides. As of 2003, more than 400 anthocyanins had been reported, [51] while later literature in early 2006, puts the number at more than 550 different anthocyanins. The difference in chemical structure that occurs in response to changes in pH, is the reason why anthocyanins often are used as pH indicators, as they change from red in acids to blue in bases through a process called halochromism.

Stability Edit

Anthocyanins are thought to be subject to physiochemical degradation in vivo and in vitro. Structure, pH, temperature, light, oxygen, metal ions, intramolecular association, and intermolecular association with other compounds (copigments, sugars, proteins, degradation products, etc.) generally are known to affect the color and stability of anthocyanins. [52] B-ring hydroxylation status and pH have been shown to mediate the degradation of anthocyanins to their phenolic acid and aldehyde constituents. [53] Indeed, significant portions of ingested anthocyanins are likely to degrade to phenolic acids and aldehyde in vivo, following consumption. This characteristic confounds scientific isolation of specific anthocyanin mechanisms in vivo.

PH Edit

Use as environmental pH indicator Edit

Anthocyanins may be used as pH indicators because their color changes with pH they are red or pink in acidic solutions (pH < 7), purple in neutral solutions (pH ≈ 7), greenish-yellow in alkaline solutions (pH > 7), and colorless in very alkaline solutions, where the pigment is completely reduced. [55]

  1. Anthocyanin pigments are assembled like all other flavonoids from two different streams of chemical raw materials in the cell:
    • One stream involves the shikimate pathway to produce the amino acid phenylalanine, (see phenylpropanoids)
    • The other stream produces three molecules of malonyl-CoA, a C3 unit from a C2 unit (acetyl-CoA), [56]
  2. These streams meet and are coupled together by the enzyme chalcone synthase, which forms an intermediate chalcone-like compound via a polyketide folding mechanism that is commonly found in plants,
  3. The chalcone is subsequently isomerized by the enzyme chalcone isomerase to the prototype pigment naringenin,
  4. Naringenin is subsequently oxidized by enzymes such as flavanone hydroxylase, flavonoid 3'-hydroxylase, and flavonoid 3',5'-hydroxylase,
  5. These oxidation products are further reduced by the enzyme dihydroflavonol 4-reductase to the corresponding colorless leucoanthocyanidins, [57]
  6. Leucoanthocyanidins once were believed to be the immediate precursors of the next enzyme, a dioxygenase referred to as anthocyanidin synthase, or, leucoanthocyanidin dioxygenase flavan-3-ols, the products of leucoanthocyanidin reductase (LAR), recently have been shown to be their true substrates,
  7. The resulting unstable anthocyanidins are further coupled to sugar molecules by enzymes such as UDP-3-O-glucosyltransferase, [58] to yield the final relatively-stable anthocyanins.

Thus, more than five enzymes are required to synthesize these pigments, each working in concert. Even a minor disruption in any of the mechanisms of these enzymes by either genetic or environmental factors, would halt anthocyanin production. While the biological burden of producing anthocyanins is relatively high, plants benefit significantly from the environmental adaptation, disease tolerance, and pest tolerance provided by anthocyanins.

In anthocyanin biosynthetic pathway, L-phenylalanine is converted to naringenin by phenylalanine ammonialyase (PAL), cinnamate 4-hydroxylase (C4H), 4-coumarate CoA ligase (4CL), chalcone synthase (CHS), and chalcone isomerase (CHI). Then, the next pathway is catalyzed, resulting in the formation of complex aglycone and anthocyanin through composition by flavanone 3-hydroxylase (F3H), flavonoid 3'-hydroxylase (F3′H), dihydroflavonol 4-reductase (DFR), anthocyanidin synthase (ANS), UDP-glucoside: flavonoid glucosyltransferase (UFGT), and methyl transferase (MT). Among those, UFGT is divided into UF3GT and UF5GT, which are responsible for the glucosylation of anthocyanin to produce stable molecules. [59]

Genetic analysis Edit

The phenolic metabolic pathways and enzymes may be studied by mean of transgenesis of genes. The Arabidopsis regulatory gene in the production of anthocyanin pigment 1 (AtPAP1) may be expressed in other plant species. [61]

Anthocyanins have been used in organic solar cells because of their ability to convert light energy into electrical energy. [62] The many benefits to using dye-sensitized solar cells instead of traditional p-n junction silicon cells, include lower purity requirements and abundance of component materials, as well as the fact that they may be produced on flexible substrates, making them amenable to roll-to-roll printing processes. [63]

Anthocyanins fluoresce, enabling a tool for plant cell research to allow live cell imaging without a requirement for other fluorophores. [64] Anthocyanin production may be engineered into genetically-modified materials to enable their identification visually. [65]

6 Major Types of Inflorescence (With Diagrams) | Botany

The following points highlight the six major types of inflorescence. After reading this article you will learn about: 1. Racemose Inflorescence 2. Cymose Inflorescence 3. Compound 4. Cyathium 5. Verticillaster 6. Hypanthodium.

Inflorescence: Type # 1. Racemose Inflorescence:

In this type of inflorescence the main axis does not end in a flower, but it grows continuously and develops flowers on its lateral sides in acropetal succession (i.e., the lower or outer flowers are older than the upper or inner ones). The various forms of racemose inflorescence may be described under three heads.

(i) With the main axis elongated, i.e., (a) raceme (b) spike (c) spikelets (d) catkin and (e) spadix.

(ii) With the main axis shortened, i.e., (i) corymb and (ii) umbel.

(iii) With the main axis flattened, i.e., capitulum or head.

(i) Main Axis Elongated:

In such cases the main axis remains elongated and it bears laterally a number of stalked flowers. The lower or older flowers possess longer stalks than the upper or younger ones, e.g., radish (Raphanus sativus), mustard (Brassica campestris), etc.

When the main axis of raceme is branched and the lateral branches bear the flowers, the inflorescence is known as compound raceme or panicle, e.g., neem (Azadirachta indica), gul-mohar (Delonix regia), etc.

The main axis of the inflorescence together with the latest axes, if present, is termed as the peduncle. The stalk of the individual flower of the inflorescence is called the pedicel.

In this type of racemose inflorescence the main axis remains elongated and the lower flowers are older, i.e., opening earlier than the upper ones, as found in raceme, but here the flowers are sessile, i.e., without pedicel or stalk, e.g., amaranth (Amaranthus spp.), latjira (Achyranthes aspera), etc.

Each spikelet may bear one to several flowers (florets) attached to a central stalk known as rachilla. Spikeletes are arranged in a spike inflorescence which is composed of several to many spikelets which are combined in various manners on a main axis called the rachis. Some are in compound spikes (i.e., in wheat—Triticum aestivum), others are in racemes (e.g., in Festuca), while some are in panicles (e.g., in Avena).

The usual structure of spikelet is as— There is a pair of sterile glumes at the base of spikelet, the lower, outer glume called the first, and the upper, inner one called the second. Just above the glumes, there is series of florets, partly enclosed by them.

Each floret has at its base a lemma and palea. The lemma is the lower, outer bract of the floret. Usually the lemma also known as inferior palea bears a long awn as an extension of the mid-rib at the apex or back.

The floral parts borne in the axil of lemma. The palea (also known as superior palea) often with two longitudinal ridges (keels or nerves), stands between the lemma and the rachilla. Flowers and glumes are arranged on the spikelet in two opposite rows. Spikeletes are characteristic of Poaceae (Gramineae) or Grass family, e.g., grasses, wheat, barley, oats, sorghum, sugarcane, bamboo, etc.

This is a modified spike with a long and drooping axis bearing unisexual flowers, e.g., mulberry (Moras alba), birch (Betula spp.), oak (Quercus spp.), etc.

This is also a modification of spike inflorescence having a fleshy axis, which remains enclosed by one or more large, often brightly coloured bracts, the spathes, e.g., in members of Araceae, Musaceae and Palmaceae. This inflorescence is found only in monocotyledonous plants.

(ii) Main Axis Shortened:

In this inflorescence the main axis remains comparatively short and the lower flowers possess much longer stalks or pedicels than the upper ones so that all the flowers are brought more or less to the same level, e.g., in candytuft (Iberis amara).

In this inflorescence the primary axis remains comparatively short, and it bears at its tip a group of flowers which possess pedicels or stalks of more or less equal lengths so that the flowers are seen to spread out from a common point. In this inflorescence a whorl of bracts forming an involucre is always present, and each individual flower develops from the axil of a bract.

Generally the umbel is branched and is known as umbel of umbels (compound umbel), and the branches bear flowers, e.g., in coriander (Coriandrum sativum), fennel, carrot, etc. Sometimes, the umbel is un-branched and known as simple umbel, e.g., Brahmi (Centella asiatica). This inflorescence (umbel) is characteristic of Apiaceae (Umbelliferae) family.

(iii) Main Axis Flattened:

In this type of inflorescence the main axis or receptacle becomes suppressed, and almost flat, and the flowers (also known as florets) are sessile (without stalk) so that they become crowded together on the flat surface of the receptacle. The florets are arranged in a centripetal manner on the receptacle, i.e., the outer flowers are older and open earlier than the inner ones.

The individual flowers (florets) are bracteate. In addition the whole inflorescence remains surrounded by a series of bracts arranged in two or three whorls.

The flowers (florets) are usually of two kinds:

(i) Ray florets (marginal strap-shaped flowers) and

(ii) Disc florets (central tubular flowers).

The capitulum (head) may also consist of only one kind of florets, e.g., only tubular florets in Ageratum or only ray or strap-shaped florets in Sonchus. A capitulum or head is characteristic of Asteraceae (Compositae) family, e.g., sunflower (Helianthus annuus), marigold (Tagetes indica), safflower (Carthamus tinctorius). Zinnia, Cosmos, Tridax, Vernonia, etc. Besides, it is also found in Acacia and sensitive plant (Mimosa pudica) of Mimosaceae family.

The capitulum inflorescence has been considered to be the most perfect. The reasons are as follows:

The individual flowers are quite small and massed together in heads, and therefore, they add to greater conspicuousness to attract the insects and flies for pollination.

At the same time there is a considerable saving of material in the construction of the corolla and other floral parts.

A single insect may pollinate flowers in a short time without flying from one flower to another.

Inflorescence: Type # 2. Cymose Inflorescence:

In this type of inflorescence the growth of the main axis is ceased by the development of a flower at its apex, and the lateral axis which develops the terminal flower also culminates in a flower and its growth is also ceased. The flowers may be pedicellate (stalked) or sessile (without stalk).

Here the flowers develop in basipetal succession, i.e., the terminal flower is the oldest and the lateral ones younger. This type of opening of flowers is known as centrifugal.

The cymose inflorescence may be of four main types:

(i) Uniparous or monochasial cyme

(ii) Biparous or dichasial cyme

(iii) Multiparous or polychasial cyme and

(i) Uniparous or Monochasial Cyme:

Here the main axis ends in a flower and it produces only one lateral branch at a time ending in a flower. The lateral and succeeding branches again produce only one branch at a time like the primary one.

There are three forms of uniparous cyme:

(a) Helicoid Cyme:

When the lateral axes develop successively on the same side, forming a sort of helix, the cymose inflorescence is known as helicoid or one-sided cyme, e.g., in Begonia, Juncus, Hemerocallis and some members of Solanaceae.

(b) Scorpioid Cyme:

When the lateral branches develop on alternate sides, forming a zigzag, the cymose inflorescence is known as scorpioid or alternate-sided cyme, e.g., in Gossypium (cotton), Drosera (sundew), Heliotropium, Freesia, etc.

(c) Symopodial Cyme:

Sometimes, in monocha­sial or uniparous cyme successive axes may be at first curved or zig-zag (as in scorpioid cyme) but later on it becomes straight due to rapid growth, thus forming a central or pseudoaxis. This type of inflorescence is known as sympodial cyme as found in some members of Solanaceae (e.g., Solanum nigrum).

(ii) Biparous or Dichasial Cyme:

In this type of inflorescence the peduncle bears a terminal flower and stops growing. At the same time the peduncle produces two lateral younger flowers or two lateral branches each of which terminates in a flower.

There are three flowers the oldest one is in the centre. The lateral and succeeding branches in their turn behave in the same manner, e.g., jasmine, teak, Ixora, Saponaria, etc. This is also known as true cyme or compound dichasium.

(iii) Multiparous or Polychasial Cyme:

In this type of cymose inflorescence the main axis culminates in a flower, and at the same time it again produces a number of lateral flowers around. The oldest flower is in the centre and ends the main floral axis (peduncle). This is a simple polychasium.

The whole inflorescence looks like an umbel, but is readily distinguished from the latter by the opening of the middle flower first, e.g., Ak (Calotropis procera), Hamelia patens, etc.

(iv) Cymose Capitulum:

This type of inflorescence is found in Acacia, Mimosa and Albizzia. In such cases the peduncle is reduced or condensed to a circular disc. It bears sessile or sub-sessile flowers on it. The oldest flowers develop in the centre and youngest towards the periphery of the disc, such arrangement is known as centrifugal. The flowers make a globose head, which is also called glomerule.

Inflorescence: Type # 3. Compound Inflorescence:

In this type of inflorescence the main axis (peduncle) branches repeatedly once or twice in racemose or cymose manner. In the former case it becomes a compound raceme and in the latter case it becomes a compound cymose inflorescence.

The main types of compound inflorescence are as follows:

1. Compound Raceme or Panicle:

In this case the raceme is branched, and the branches bear flowers in a racemose manner, e.g., Delonix regia, Azadirachta indica, Clematis buchaniana, Cassia fistula, etc.

Also known as umbel of umbels. Here the peduncle (main axis) is short and bears many branches which arise in an umbellate cluster. Each such branch bears a group of flowers in an umbellate manner. Usually a whorl of leafy bracts is found at the base of branches and also at the bases of flowers arranged in umbellate way.

The former whorl of bracts is called involucre and the latter involucel. Typical examples of compound umbel are—Daucus carota (carrot), Foeniculum vulgare (fennel), Coriandrum sativum (coriander), etc.

Also known as corymb of corymbs. Here the main axis (peduncle) branches in a corymbose manner and each branch bears flowers arranged in corymbs. Typical example-cauliflower.

Also known as spike of spikelets. The typical examples are found in Poaceae (Gramineae) family such as-wheat, barley, sorghum, oats, etc. This type has already been described under sub-head spikelets.

Also known as spadix of spadices. Here the main axis (peduncle) remains branched in a racemose manner and each branch bears sessile and unisexual flowers. The whole branched structure remains covered by a single spathe. The examples are common in Palmaceae (Palmae) family.

Also known as head of heads or capitulum of capitula. In this case many small heads form a large head. The typical example is globe thistle (Echinops). In this plant the heads are small and one-flowered and are arranged together forming a big compound head.

Inflorescence: Type # 4 . Cyathium:

This type of inflorescence is found in genus Euphorbia of family Euphorbiaceae also found in genus Pedilanthus of the family. In this inflorescence there is a cup-shaped involucre, often provided with nectar secreting glands. The involucre encloses a single female flower, represented by a pistil, in the centre, situated on a long stalk.

This female flower remains surrounded by a number of male flowers arranged centrifugally. Each male flower is reduced to a solitary stalked stamen. It is evident that each stamen is a single male flower from the facts that it is articulated to a stalk and that it possesses a scaly bract at the base. The examples can be seen in poinsettia (Euphorbia), Pedilanthus, etc.

Inflorescence: Type # 5 . Verticillaster:

This type of inflorescence is a condensed form of dichasial (biparous) cyme with a cluster of sessile or sub-sessile flowers in the axil of a leaf, forming a false whorl of flowers at the node. The first of main floral axis gives rise to two lateral branches and these branches and the succeeding branches bear only one branch each on alternate sides.

The type of inflorescence is characteristic of Lamiaceae (Labiatae) family. Typical examples, are—Ocimum, Coleus, Mentha, Leucas, etc.


Pyrethrins are pesticides found naturally in some chrysanthemum flowers. They are a mixture of six chemicals that are toxic to insects. Pyrethrins are commonly used to control mosquitoes, fleas, flies, moths, ants, and many other pests.

Pyrethrins are generally separated from the flowers. However, they typically contain impurities from the flower. Whole, crushed flowers are known as pyrethrum powder.

Pyrethrins have been registered for use in pesticides since the 1950’s. They have since been used as models to produce longer lasting chemicals called pyrethroids, which are man-made.

What are some products that contain pyrethrins?

Currently, pyrethrins are found in over 2,000 registered pesticide products. Many of these are used in and around buildings and on crops and ornamental plants. Others are used on certain pets and livestock. Pyrethrins are commonly found in foggers (bug bombs), sprays, dusts and pet shampoos. Some of these products can be used in organic agriculture. Pyrethrins are also found in some head lice products regulated by the Food and Drug Administration.

Always follow label instructions and take steps to avoid exposure. If any exposures occur, be sure to follow the First Aid instructions on the product label carefully. For additional treatment advice, contact the Poison Control Center at 1-800-222-1222. If you wish to discuss a pesticide problem, please call 1-800-858-7378.

How do pyrethrins work?

Pyrethrins excite the nervous system of insects that touch or eat it. This quickly leads to paralysis and ultimately their death. Pyrethrins are often mixed with another chemical to increase their effect. This second chemical is known as a synergist.

How might I be exposed to pyrethrins?

Exposure can occur if you breathe it in, get it on your skin or eyes, or eat it. For example, exposure can occur while applying sprays or dusts during windy conditions. This can also happen if you apply a product in a room that is not well ventilated. People using foggers may be exposed, especially if they come back too early or fail to ventilate properly. Exposure can also occur if you use a pet shampoo without wearing gloves. You can limit your exposure and reduce the risk by carefully following the label instructions.

What are some signs and symptoms from a brief exposure to pyrethrins?

In general, pyrethrins are low in toxicity to people and other mammals. However, if it gets on your skin, it can be irritating. It can also cause tingling or numbness at the site of contact.

Children who have gotten lice shampoo containing pyrethrins in their eyes have experienced irritation, tearing, burns, scratches to the eye, and blurred vision. When inhaled, irritation of the respiratory passages, runny nose, coughing, difficulty breathing, vomiting and diarrhea have been reported.

Dogs fed extremely large doses of pyrethrins have experienced drooling, tremors, uncoordinated movement, and difficulty breathing. Increased activity, exhaustion, convulsions, and seizures have also been reported with high doses.

When exposed to pyrethrins, people have reported some of the same symptoms that are associated with asthma. These include wheeze, cough, difficulty breathing, and irritation of the airways. However, research has not found a link between exposure to pyrethrins and the development of asthma or allergies.

What happens to pyrethrins when it enters the body?

When eaten or inhaled, pyrethrins are absorbed into the body. However, they are absorbed poorly by skin contact. Once inside, they are rapidly broken down into inactive products and are removed from the body. In a study with mice, more than 85 percent left the body in feces or urine within two days. Removal of pyrethrin 1, a major component of pyrethrins, from goats and hens was also very rapid. However, studies have found very small amounts in the milk and eggs of exposed animals.

Are pyrethrins likely to contribute to the development of cancer?

In two studies, mice and rats were fed low to high doses daily for 1.5 to 2 years. At the highest dose, some rats had an increased number of liver tumors. However, the changes in the liver leading to tumors only occurred above a certain threshold. Based on these studies, the EPA has classified pyrethrins as not likely to cause cancer. However, this rating is limited to doses below this threshold.

Has anyone studied non-cancer effects from long-term exposure to pyrethrins?

In separate studies, rats and dogs were fed low to moderate daily doses of pyrethrins for one to two years. At moderate doses, there were effects to the thyroid in rats and the liver in dogs. In another study, rats breathed in low to moderate doses daily for several months. At low doses, damage to tissue along the nasal and respiratory passages was observed. At moderate doses, lower body weights, difficulty breathing, and tremors were observed.

Scientists have also tested whether pyrethrins cause developmental or reproductive effects in rats and rabbits. In these studies, animals were fed low to moderate doses daily throughout their lives or during their pregnancies. Effects were only observed at moderate doses. These included lower body weights in some adult rats and their young. Drooling, unusual postures, and difficulty breathing were observed in one adult rabbit. Also, two rabbits lost their pregnancies. However, it is unclear if the lost pregnancies were related to pyrethrins. No effects were observed in rats or their young when fed solely during their pregnancies.

Are children more sensitive to pyrethrins than adults?

Children may be especially sensitive to pesticides compared to adults. However, there are currently no conclusive data showing that children have increased sensitivity specifically to pyrethrins.

What happens to pyrethrins in the environment?

In the presence of sunlight, pyrethrin 1, a component of pyrethrins, breaks down rapidly in water and on soil and plant surfaces. Half-lives are 11.8 hours in water and 12.9 hours on soil surfaces. On potato and tomato leaves, less than 3% remained after 5 days. Pyrethrins do not readily spread within plants.

In the absence of light, pyrethrin 1 breaks down more slowly in water. Halflives of 14 to 17 days have been reported. When water was more acidic, pyrethrin 1 did not readily break down. Pyrethrins that enter the water do not dissolve well but tend to bind to sediment. Half-lives of pyrethrin 1 in sediment are 10.5 to 86 days.

Pyrethrins also stick to soil and have a very low potential to move through soil towards ground water. In field studies, pyrethrins were not found below a soil depth of 15 centimeters. However, pyrethrins can enter water through soil erosion or drift. In the top layers of soil, pyrethrins are rapidly broken down by microbes. Soil half-lives of 2.2 to 9.5 days have been reported. Pyrethrins have a low potential to become vapor in the air.

Can pyrethrins affect birds, fish, or other wildlife?

Pyrethrins are practically non-toxic to birds but highly toxic to honey bees. However, some of the risk to pollinators is limited by their slight repellent activity and rapid breakdown.

Pyrethrins are highly to very highly toxic to fish. They are also very highly toxic to lobster, shrimp, oysters, and aquatic insects. This may be partly due to their higher toxicity at lower temperatures. There is evidence that long term exposure to pyrethrins can cause reproductive effects in fish and aquatic insects. In separate studies, minnows and water fleas were exposed to very small amounts of pyrethrins for one month. Fewer minnow eggs hatched and fewer water flea young were produced.

Mammals of Washington

habits : Mostly nocturnal, constructs burrows, occasionally diverts streams into its tunnels.

identification : Very short tail, white spot just below ear. Total length: 25-45 cm tail: 20-55 mm mass: 500-1500 g.

Range in Washington : Introduced, mainly in cities.

habitat : City parks and yards.

identification : Gray with reddish tones, silvery-tipped hairs. Occasionally black or albino. Total length: 40-50 cm tail: 21-24 cm mass: 400-700 g.

Range in Washington : South Puget Sound Prairie southern Cascades in Klickitat County lower eastern slope of North Cascades.

habitat : Oak woodland, mixed with conifers.

identification : Large and slate-gray with white belly, tail large and extremely bushy. Total length: 45-60 cm tail: 25-30 cm mass: 350-950 g.

Range in Washington : Introduced, mainly in cities.

identification : Largest tree squirrel, large bushy tail with yellow-tipped hairs. Three color morphs: grey, black, or reddish. Total length: 45-70 cm tail: 20-35 cm mass: 500-1000 g.

Range in Washington : Cascades and west.

habitat : Coniferous forest.

habits : Territorial, hoards piles of cones, does not hibernate.

identification : Dark gray with orange-yellow beneath. Total length: 270-355 mm tail: 100-155 mm mass: 150-300 g.

Range in Washington : Northward and eastward from Lake Chelan Blue Mountains of southeastern Washington.

habitat : Coniferous forest.

habits : Territorial, hoards piles of cones, highly arboreal.

identification : Gray with some red tinge, white beneath. Total length: 270-385 mm tail: 90-155 mm mass: 140-250 g.

Range in Washington : Cascades.

identification : Black and whitish markings on head and shoulders, nose and patch between eyes whitish. Total length: 45-80 cm tail: 15-25 cm mass: 4-9 kg.

Range in Washington : East of Cascades.

habitat : Open rocky areas, treeless habitat.

identification : Yellow belly, whitish spot between eyes. Total length: 45-70 cm tail: 13-22 cm mass: 2-5 kg.

Range in Washington : Olympic Mountains. In 2009 this species was designated as Washington State's official endemic mammal, occurring only within the state of Washington.

habits : Hibernates October to May.

identification : Brownish mixed with white very similar and closely related to hoary marmot. Total length: 45-80 cm tail: 15-25 cm mass: 4-9 kg.

Range in Washington : South-Central Washington.

identification : Brown with whitish flecking, light wash on sides of neck across shoulders to haunches, darker "V" on back. Total length: 35-50 cm tail: 15-25 cm mass: 280-740 g.

Range in Washington : Extreme northeastern and southeastern corners of the state.

habitat : Wooded and open rocky areas.

diet : Herbivore, also fungus.

identification : Body stripes like chipmunks, but no head stripes. Head and shoulders coppery-red. Total length: 25-30 cm tail: 6-12 cm mass: 175-275 g.

General range : Cascades of Washington and extreme southern British Columbia.

Range in Washington : Cascades.

habitat : Wooded and open rocky areas.

diet : Herbivore, also fungus.

identification : Body stripes like chipmunks, but no head stripes. Upper pair of dark lines faint. Head and shoulders coppery-red. Total length: 25-30 cm tail: 6-12 cm mass: 175-275 g.

Range in Washington : Eastern Washington.

habitat : Meadows and fields, associated with forests.

identification : Gray with yellow-orange beneath, tail bushy. Total length: 30-40 cm tail: 8-12 cm mass: 350-800 g.

General range : Southeast Oregon, Snake River Valley of Idaho, Nevada (except extreme south) extreme eastern central California, and western Utah.

Range in Washington : North of Yakima and west of Columbia River disjunct from the rest of the species.

habitat : Sagebrush and grasslands.

identification : Gray no spots short tail. Total length: 17-27 cm tail: 3-7 cm mass: 125-325 g.

General range : Recently recognized as a species occurring only in Washington.

Range in Washington : Southeast Washington south of Yakima River and west and north of Columbia River. Current recognition of this species does not include populations north of the Yakima River, which are considered to be Urocitellis mollis.

habitat : Grassland and sagebrush.

identification : Gray no spots short tail that is reddish below. Total length: 17-27 cm tail: 3-7 cm mass: 125-325 g.

General range : Southeastern Washington and small area of Oregon in Gilliam, Morrow, and Umatilla Counties.

Range in Washington : East of Columbia River from center of state southward.

habitat : Sagebrush and grassland.

identification : Gray white spots short tail with blackish tip. Total length: 18-25 cm tail: 3-7 cm mass: 150-280 g.

conservation : State Candidate Federal Candidate.

Range in Washington : Olympics, Cascades and east.

habitat : Forest and brush.

diet : Seeds, flowers, fruits.

identification : Stripes on body and head brightly colored underside of tail brownish-yellow. Total length: 180-245 mm tail: 70-100 mm mass: 30-73 g.

Range in Washington : Central eastern Washington.

diet : Seeds, flowers, fruits.

identification : Stripes on body and head that continue to base of tail. Smallest, lightest chipmunk in Washington. Total length: 160-225 mm tail: 70-115 mm mass: 30-70 g.

Range in Washington : Mountains of the extreme northeast.

habitat : Coniferous forests, talus slopes.

diet : Seeds, flowers, fruits.

identification : Stripes on body and head rump gray tail rufous above, dark reddish below closely related to T. amoenus . Total length: 22-25 cm tail: 10-12 cm mass: about 60 g.

Range in Washington : Cascades and west.

habitat : Coniferous forest and brush.

diet : Seeds, flowers, fruits.

identification : Stripes on body and head, brownish stripe below ears. Largest, darkest chipmunk in Washington. Total length: 220-315 mm tail: 90-150 mm mass: 50-110 g.

Range in Washington : All forested regions of the state.

habitat : Coniferous and mixed forests.

habits : Nocturnal glides from trees highly arboreal does not hibernate.

identification : Gliding skin between front and rear legs large eyes. Total length: 25-35 cm tail: 12-18 cm mass: 45-70 g

Range in Washington : Wet areas throughout the state.

habitat : Ponds, lakes, slow streams.

habits : Aquatic, builds dams and lodges.

identification : Largest rodent in North America, flat scaly tail. Total length: 90-115 cm tail: 30-45 cm mass: 20-27 kg.

Photo by US Fish & [email protected] Commons.

Range in Washington : Southern Columbia Basin.

habitat : Sagebrush, sandy areas.

habits : Locomotion mainly bipedal.

identification : Long hind feet and tail, large head. Striped tail, with white tail stripes narrower than dark tail stripes. Total length: 200-280 mm tail: 100-165 mm mass: 50-95 g.

Photo by Jim Kenagy.

Range in Washington : East of Cascades.

diet : Granivore accumulates seed cache for winter.

habits : Hibernates. Locomotion mainly quadrupedal.

identification : Brownish, white beneath. Long tail, slightly crested toward tip. Total length: 150-200 mm tail: 75-105 mm mass: 17-31 g.

Range in Washington : Olympics and Tacoma area southward.

habitat : Most open habitats.

habits : Digs burrows with forelimbs and teeth, forages below ground, forms soil mounds.

identification : Pointed ear with black patch behind. Short tail, heavy jaw bone, big incisors. Total length: 180-240 mm tail: 50-80 mm mass: 50-95 g.

Photo by Kelli Wood.

Range in Washington : Cascades and east.

habitat : Most open habitats.

habits : Digs burrows with forelimbs and teeth, forages below ground, forms soil mounds.

identification : Rounded ear with black patch behind. Short tail, heavy jaw bone, big incisors. Total length: 165-230 mm tail: 40-75 mm mass: 75-130 g.

Range in Washington : Mountains of northeast and southeast.

habitat : Meadows and thickets near streams.

diet : Granivore, herbivore.

habits : Hibernates may drum the ground with its tail when alarmed.

identification : Golden sides dark back long tail enlarged hind feet. Total length: 21-26 cm tail: 13-16 cm mass: 15-38 g.

Range in Washington : Cascades and west.

habitat : Meadows in coniferous forests.

diet : Granivore, herbivore.

habits : Hibernates may drum the ground with its tail when alarmed.

identification : Golden sides dark back long tail enlarged hind feet. Total length: 21-26 cm tail: 13-16 cm mass: 15-38 g.

Range in Washington : East of Cascades.

identification : Pale gray above, whitish below and on feet short tail. Total length: 10-15 cm tail: 1.5-3 cm mass: 17-38 g.

General range : Clark County, Washington and Willamette Valley of Oregon.

habitat : Grassy and agricultural lands.

identification : Tail bicolored and short. Total length: 14-20 cm tail: 3-7 cm mass: 35-85 g.

Range in Washington : Throughout the state except in sagebrush scrub.

identification : Tail bicolored grayish-brown above, light gray below. Total length: 15-25 cm tail: 5-12 cm mass: 20-85 g.

Range in Washington : Eastern base of the Cascades and eastward.

habitat : Wet meadows in forested areas.

identification : Tail bicolored feet dusky or silvery-gray. Total length: 14-20 cm tail: 3-7 cm mass: 35-85 g.

Range in Washington : Cascades and west.

habitat : Grassland or forest.

identification : Brown above, silvery below. Total length: 12-16 cm tail: 3-5 cm mass: 15-30 g.

Range in Washington : Northeastern Washington.

identification : Gray with silver-tipped hair below. Total length: 14-20 cm tail: 3-6 cm mass: 20-70 g.

Range in Washington : Cascades and Blue Mountains.

habitat : Marshes, streams, and wet meadows.

identification : Grayish to reddish above, white to silver below long bicolored tail. Total length: 20-26 cm tail: 7-9 cm.

Range in Washington : Western Washington lowlands.

habitat : Marshes, streams, and wet meadows.

identification : Dark brown above, gray below feet dusky large ears. Total length: 15-25 cm tail: 5-8 cm mass: 40-100 g.

Range in Washington : Statewide in mountains.

habitat : Forest or meadows in mountains.

identification : Short tail red back. Total length: 12-16 cm tail: 3-5 cm mass: 16-42 g.

Range in Washington : Statewide.

habitat : Marshes and ponds.

identification : Tail slightly flattened for swimming large compared to other members of its family. Total length: 41-62 cm tail: 18-30 cm mass: 540-1800 g.

Range in Washington : High mountains.

habitat : Forests or meadows in high mountains.

identification : Grizzled brown above, silver below white feet. Total length: 13-15 cm tail: 2-4 cm mass: 15-40 g.

Range in Washington : Northern border of state.

identification : Brown above, gray below short, bicolored tail. Total length: 12-14 cm tail: 2-3 cm mass: 25-35 g.

Range in Washington : Statewide.

habitat : Many habitats, often associated with rocks.

habits : The original "Packrat" collects objects, preferably shiny.

identification : Very large body size bushy tail. Total length: 30-45 cm tail: 12-25 cm mass: 155-445 g.

Range in Washington : East of Cascades.

diet : Insects strong predatory behavior.

identification : Grayish or buff above, white below bicolored tail with white tip. Total length: 13-20 cm tail: 3-6 cm mass: 27-52 g.

Photo by US National Park [email protected] Commons.

Range in Washington : Most of state.

identification : Grayish-brown above, white below. Similar to P. keeni but tail shorter. Total length: 12-21 cm tail: 5-11 cm mass: 10-33 g.

Range in Washington : Western Washington.

identification : Grayish-brown above, white below. Similar to P. maniculatus, but tail longer. Total length: 12-22 cm tail: 5-12 cm mass: 10-33 g.

Range in Washington : East of Cascades.

habitat : Grassland, marshes.

diet : Seeds, plants, insects.

identification : Ears partly furred smaller than Peromyscus. Total length: 11-17 cm tail: 5-10 cm mass: 9-22 g.

General range : Throughout most of the world in close association with humans.

Range in Washington : Human habitations and all nearby habitats. Introduced.

habitat : Buildings, areas with good cover, cultivated fields.

diet : Opportunistic seeds, human food, insects.

identification : Grayish-brown above, nearly the same color below. Total length: 13-20 cm tail: 6-10 cm mass: 18-23 g.

General range : Worldwide in warmer climates, restricted to habitats modified by humans.

Range in Washington : Urban areas sometimes nearby habitats. Introduced.

habitat : Human dwellings, cities, cultivated fields.

identification : Brownish-gray above, grayish below scaly tail. Total length: 30-45 cm tail: 12-20 cm mass: 195-485 g.

General range : Worldwide in tropic and temperate zones.

Range in Washington : Human habitations and nearby habitats. Introduced.

habitat : Seaports and buildings.

identification : Brownish or grayish above, lighter below sparsely-haired tail. Total length: 30-45 cm tail: 16-25 cm mass: 115-350 g.

Range in Washington : Statewide.

diet : Herbivore twigs, leaves of trees.

identification : Quills cover body. Total length: 65-93 cm tail: 15-30 cm mass: 4-18 kg.

Photo by [email protected]

Range in Washington : Introduced along rivers and Puget Sound.

identification : Large aquatic rodent tail round and scaly. Total length: 65-140 cm tail: 30-45 cm mass: 2-12 kg.

Black-Capped Chickadee Nest, Eggs and Young Photographs

Black-capped Chickadee nest in ANBS box. Photo by Bet Zimmerman. Notice evergreen buds, moss, bits of bark in base. This nest filled up about 1/4 to 1/3 of the box.

Nest Description: Downy nest with moss base, topped with fur and soft plant fibers. Female may cover eggs with moss/fur when leaving the box. Very thin-shelled white/cream eggs with light brown/reddish speckles, dots or blotches, little or no gloss, spots may be concentrated more on the wide end of the egg.

More about chickadees biology, nesting behavior and timetable.

Black-capped Chickadee nest in a Gilberston box. Photo by Bet Zimmerman.

Chickadees are capable of excavating their own cavity. They may prefer birches for excavation because the outer bark stays intact, while the inner bark gets soft when rotten. This may explain why they seem to be attracted to Gilberston PVC boxes painted to look like white birches.

Chickadee nests can be confused with Tufted Titmouse nests, especially in the early stages of construction.

A Black-capped Chickadee nest in a Gilbertson box, with no nesting material underneath. Photo by Bet Zimmerman.

The box is in a wooded area with no wren guard. The nest and eggs were removed two days later by a House Wren.

Photo by Pam Spielmann of NJ. ELEVEN eggs in one nest! Although chickadees may dump eggs in the nests of others, this was not egg dumping, as one egg was added every day. (It's possible that another female showed up after the first was done laying, but that would be unlikely.) 6-8 eggs are typical, 13 were recorded once.

Photo by Ed Wagaman of West Virginia.

Black-capped Chickadee nest. Photo by Peter Kwa. There are two eggs (part of one is visible) to the right of the nestling in the nestcup, which did not hatch.

The floor size on this nestbox is 4" x 4" so that the nestcup can be estimated to be about 2" diameter. The moss base is about 1" to 1.5" thick.

1/2" of pine shavings were placed under the moss base to entice Chickadees to nest. Most of the shavings were 'excavated' by the Chickadees. The fur lining is dog fur put in a suet cage about 20 feet away from the nestbox.

At 8 days, the nestling was observed reaching for its preening gland and going through the motions of preening, even though it barely had feathers.

Another BCCH nest in a Gilbertson box. Photo by Bet Zimmerman. Notice two unhatched eggs eggs.

Chickadees have also been known to nest in rotted wooden fence posts and open stumps. See photos.

12 day old BCCH nestlings. Photo by Linda Moore. Only 2 of the 5 eggs that were laid hatched.

The fur from Linda's golden retriever was used. She was surprised at how quickly the nest was constructed. They can make a nest in 3-4 days. See All About Chickadees.

The student of Nature wonders the more and is astonished the less, the more conversant he becomes with her operations but of all the perennial miracles she offers to his inspection, perhaps the most worthy of admiration is the development of a plant or of an animal from its embryo.
-Thomas Henry Huxley, British biologist and educator. Reflection #54, Aphorisms and Reflections, selected by Henrietta A. Huxley, Macmillan, 1907.

May all your blues be birds!

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Last updated March 24, 2016 . Design by Chimalis.

Types of Permanent Tissues: 2 Types (With Diagram) | Plants

A simple permanent tissue is that tissue which is made up of similar permanent cells that carry out the same function or similar set of functions. Simple permanent tissues are of three types— parenchyma, collenchyma and sclerenchyma.

I. Parenchyma:

(Gk. para- beside, engchyma-tissue):

Parenchyma is a simple permanent living tissue which is made up of thin-walled similar isodiametric cells. It is the most abundant and common tissue of plants. Typically the cells are isodiametric (all sides equal). They may be oval, rounded or polygonal in outline.

The cell wall is made up of cellulose. Cells may be closely packed or have small intercellular spaces for exchange of gases (Fig. 6.7 B). Internally each cell encloses a large central vacuole and a peripheral cytoplasm containing nucleus. The adjacent parenchyma cells are connected with one another by plasmodesmata. They, therefore, form symplasm or living continuum.

Parenchyma is morphologically and physiologically un-specialised tissue that forms the ground tissue in the non-woody or soft areas of the stems, leaves, roots, flowers, fruits, etc. The typical parenchyma is meant for the storage of food, slow conduction of various substances and for providing turgidity to the softer parts of the plants.

It is modified variously to perform special functions:

(a) Fibre-like elongated parenchyma is called prosenchyma. It is slightly thick walled and is meant for providing rigidity and strength.

(b) Cutinised parenchymatous cells form a protective covering layer or epidermis. Epidermis is single layered. Intercellular spaces are absent. The cutin also forms a distinct layer on the outer surface of epidermal cells. It is called cuticle (Fig. 6.7 E). It reduces transpiration.

(c) The young parts of the root are covered by a layer of un-thickened and un-cutinised parenchyma cells, some of which give rise to tubular outgrowths called root hairs. It is known as piliferous layer or epiblema. This layer is specialized to absorb water and mineral salts from the soil.

(d) Xylem parenchyma is made of small and often thickened cells. It helps in the storage of food and lateral conduction of water (Fig. 6.7 D).

(e) Phloem parenchyma is formed of thin-walled elongated parenchymatous cells. It takes part both in the storage and lateral conduction of food.

(f) Parenchyma cells containing chloroplasts are collectively termed as chlorenchyma. It takes part in the manufacture of food. Chlorenchyma of leaves is called mesophyll. It is differentiated into two parts, palisade parenchyma and spongy parenchyma (Fig. 6.7 F). Cells of palisade parenchyma are columnar in shape while those of spongy parenchyma are often lobed, rounded or irregular in outline.

(g) A special parenchyma tissue is found in the aquatic plants and some land plants (e.g., petiole of Banana, Canna). It is known as aerenchyma (Fig. 6.7 G). It consists of a network of parenchyma cells which enclose very large air cavities. These air cavities store gases and make the aquatic plants light and bouyant.

(h) Storage parenchyma is made of large sized vacuolate cells which store water, mucilage and food, e.g., Aloe, Opuntia Potato tuber.

(i) Idioblasts are specialized non-green large-sized parenchyma cells which possess inclusions or ingredients like tannins, oils, crystals, etc.

(j) Secretory cells are specialized parenchyma cells that produce nectar, oil, etc.

(ii) Providing turgidity to softer parts,

(iii) Providing rigidity to tissues when prosenchymatous.

(iv) Protection and checking water loss in the form of epidermis,

(v) Formation of water absorbing epiblema in root,

(vi) Lateral conduc­tion in the form of xylem and phloem parenchyma

(vii) Photosynthesis in the form of chlorenchyma.

(viii) Providing buoyancy and storage of metabolic gases in the form of aerenchyma.

Ii. Collenchyma:

(Gk. kolla— glue, enchyma— tissue):

Collenchyma is a simple permanent tissue of retractile non-lignified living cells which possess pectocellulose thickenings in specific areas of their walls. The cells appear conspicuous­ under the microscope due to their higher refractive index.

The cells are often elongated. They are circular, oval or angular in transverse section. Internally each cell possesses a large central vacuole and a peripheral cytoplasm. Chloroplasts are often present. Wall possesses uneven longitudinal thickenings in specific areas.

Depending upon the thickening, collenchyma is of three types:

(i) Angular Collenchyma:

The thickenings are present at the angles (angular thickenings), e.g., stem of Tagetes, stem of Tomato (Fig. 6.8 B).

(ii) Lamellate Collenchyma:

The thickenings occur on the tangential walls (plate thickenings), e.g., stem of Sunflower (Fig. 6.8 A),

(iii) Lacunate Collenchyma:

The thickenings are found on the walls bordering intercellular spaces (lacunate thickenings), e.g., Cucurbita stem (Fig. 6.8 C).

Collenchyma is found below the epidermis in the petiole, leaves and stems of herba­ceous dicots, forming either continuous layers or occurring in patches, especially in the region of ridges (e.g., Gourd).

(i) It provides mechanical strength to young dicot stems, petioles and leaves,

(ii) While providing mechanical strength, collenchyma also provides flexibility to the organs and allows their bending, e.g., Cucurbita stems,

(iii) It prevents tearing of leaves,

(iv) Collenchyma allows growth and elongation of organs,

(v) Being living, its cells store food,

(vi) Its cells often contain chloroplasts and take part in photosynthesis.

Iii. Sclerenchyma:

(Gk. scleros— hard, enchyma— tissue):

Sclerenchyma is a simple supportive tissue of highly thick-walled cells with little or no protoplasm. The cell cavities are narrow. The thickening of the wall may be made up of cellulose or lignin or both. A few to numerous pits occur in the wall. Scleren­chyma is of two types, sclerenchyma fibres and sclereids.

(a) Sclerenchyma Fibres:

The scleren­chyma fibres are highly elongated (1-90 cm), narrow and spindle-shaped thick-walled cells with pointed or oblique end walls. The fibres generally occur in longitudinal bundles (Fig. 6.9A) where the pointed ends of adjacent fibres get interlocked to form a strengthening tissue.

The adjacent fibres possess simple oblique pits (un-thickened areas with common pit membranes). Bordered pits also occur in some fibres. Pits do not perform any function in the mature fibres since the latter are empty and dead.

Living firbes occur in Tamarix aphylla. They possess nucleated protoplasts for several years. Fibres are septate in phloem of Grape Vine. Sclerenchyma fibres constitute the major mechanical tissue of the plants because they can bear compression, pull, bending and shearing.

The fibres occur in all those parts where mechanical strength is required, viz., leaves, petioles, cortex, pericycle, phloem, xylem and around vascular bundles (e.g., monocot stem). Commercial fibres obtained from plants are usually sclerenchyma fibres, e.g., Jute, Flax, Hemp.

They are highly thickened dead sclerenchyma cells with very narrow cavities. Sclereids are broader as compared to the fibres being isodiametric polyhedral, spherical, oval short or cylindrical. They may also be branched.

The thick cell walls have branched or un-branched simple pits (Fig. 6.10). Being elongated, the pits of sclereids are also known as pit canals. Sclereids may occur singly or in groups. They provide stiffness to the parts in which they occur.

The impor­tant types of sclereids are as follows:

(i) Stone Cells or Brachysclereids:

Un-branched, short and isodiametric with rami-form (branched) pits, e.g., grit of Guava, Sapota, Apple and Pear.

Elongated and columnar or rod-like, e.g., epidermal covering of legume seeds.

Bone-like or columnar with swollen ends, e.g., sub-epidermal cov­ering of some legume seeds.

Branched like a star, e.g., tea leaves, petiole of Lotus.

Fibre-like, sparingly branched, e.g., Olea.

Very elongated hair-like and regularly once branched sclereids extending into intercellular spaces.

(i) Sclerenchyma is the chief mechanical tissue of the mature plant organs,

(ii) It allows the plant organs to tolerate bending, shearing, compression and pull caused by environmental factors like wind,

(iii) It provides rigidity to leaves and prevents their collapsing during temporary wilting,

(iv) Sclereids provide strength to seed cover­ings.

(v) Dehiscence of many fruits is based on differential distribution of sclerenchyma fibres, e.g., pods,

(vi) Sclereids form stony endocarp of many fruits called stone fruits, e.g., Almond, Coconut,

(vii) A number of fibres are commercially exploited, e.g., Jute (Corchorus), Flax (Linum), Hemp (Cannabis).

Type # 2. Complex Permanent Tissues:

They are permanent tissues which contain more than one type of cells. All the types of cells of a complex tissue work as a unit. The common complex permanent tissues are conducting tissues, phloem and xylem.

I. Phloem:

(Gk. phlois- inner bark Nageli, 1858):

It is a complex tissue which transports organic food inside the body of the plant. Phloem is also called bast (= bass, a vague term). It consists of four types of cells, viz., sieve tubes, companion cells, phloem parenchyma and fibres. Haberlandt (1914) uses the term leptom (e) for the conducting part of phloem.

Sieve tubes are elongated tubular conducting channels of phloem. Each sieve tube is formed of several cells called sieve tube elements or members, sieve tube cells or sieve elements. Sieve tube members are placed end to end.

The end walls are generally bulged out. They may be transverse or oblique. They have many small pores or sieve pits. Due to the presence of sieve pits the end walls are commonly called sieve plates (Fig. 6.11 A).

In some cases the end walls of sieve elements possess more than one porous area. Such an end wall is called compound sieve plate, e.g., Grape Vine, Euphorbia royleana. The sieve plates connect the protoplasts of adjacent sieve tube members.

In non-flowering plants sieve cells remain separate. They are narrower but more elon­gated as compared to individual sieve tube members. The end walls are oblique. Porous areas are less conspicuous. They are borne on the lateral walls of the elongated sieve cells. They are called sieve areas.

Internally a sieve tube member or cell has peripheral layer of cytoplasm without any nucleus (Fig. 6.11 A). The nucleus is, however, present in the young cells. The central part is occupied by a network of canals which contain fibrils of p-protein. Sieve tube takes part in the conduction of organic food.

Companion cells are narrow, elongated and thin walled living cells. They lie on the sides of the sieve tubes and are closely associated with them through compound plasmodesmata. They are squarish or rectangular in a transverse section.

The cells have dense cytoplasm and a prominent nucleus. It is supposed that the nuclei of the companion cells control the activities of the sieve tube through plasmodesmata (Fig. 6.11). Companion cells also help in main­taining a proper pressure gradient in the sieve tube elements.

Sieve tube member and its adjacent companion cells are derived from the same mother cell. Death of one results in death of the other as well. Companion cells are replaced by modified parenchyma cells (albuminous cells) in non flowering plants.

They are ordinary living elongated parenchyma cells having abundant plasmodesmata. They store food, resins, latex, mucilage, etc. The cells help in slow conduction of food, especially to the sides. Phloem parenchyma is absent in most of the monocots and some herbaceous dicots.

(d) Phloem or Bast Fibres:

Sclerenchyma fibres found in the phloem are called phloem or bast fibres. They are generally absent in primary phloem but are quite common in secondary phloem where they occur more abundant in secondary phloem as compared to primary phloem.

The fibres occur in sheets or cylinders. Phloem fibres provide mechanical strength. The textile fibres of flax, (Linum usitatissimum), hemp (Cannabis) and jute (Corchorus species) are phloem fibres.

Ii. Xylem:

Xylem is a complex tissue which performs the function of transport of water or sap inside the plant. Simultaneously, it also provides mechanical strength. Xylem is also known as wood. It consists of four types of cells, viz., tracheids, vessels (both tracheary elements), xylem or wood parenchyma and xylem or wood fibres. Out of these only tracheids and vessels take part in the transport of sap.

They are hence called tracheary elements. Vessels are the main tracheary elements of angiosperms. They are absent in gymnosperms and pteriodophytes. In the last two groups, conduction of sap is carried out by tracheids. The conducting elements of the xylem have been called hadrome by Haberlandt (1914).

The tracheids are elongated (5-6 mm dead cells with hard lignified walls, wide lumen and narrow end walls. In outline they are circular, polygonal or polyhedral.The inner walls of tracheids have various types of thickenings for mechanical strength.

The un-thickened areas allow the rapid movement of water from one tracheid to another. Tracheids constitute 90-95% of wood in gymnosperms while in angiosperms they hardly form 5% of the wood. Depend­ing upon the thickenings, tracheids are of the following types (Fig. 6.12).

In this type the thicken­ing material is laid down in the form of rings.

The thickening is deposited like a spiral or helix. Both annular and spiral thickenings are present in the first formed tracheids because they allow consid­erable stretching.

Thickening is present in the form of a network. It is supposed that it is formed by the presence of several spiral bands of thickenings which cross one another.

Here the thickenings give a ladder like appearance because they are laid down in the form of transverse bands.

It is the most advanced type of thickening. The pitted tracheids are uni­formly thickened except for small un-thickened areas called pits. In surface view they may appear circular, oval or angular. Pits often occur in pairs, that is, exactly at the same level on two adjacent elements. The pits are of two types, simple and bordered. The simple pits have uniform width of the pit chamber or cavity.

In bordered pits the pit cavity is in the form of a flask with a narrow aperture and a wide base. The area of the primary wall and middle lamella, which is present in a pit, is called pit membrane or closing membrane.

Actually it has many submicroscopic pores for the translocation of substances. A thickening called torus is present on the pit membrane of some gymnosperms for protecting the membrane from rupturing in case of unequal pressure on its two sides.

Vessels take part, like trache­ids, in the conduction of water or sap and provide mechanical support. They are much elongated tubes (3-6 metres in Eucalyptus) which are closed at either end and are formed by the union of several short, wide and thick­ened cells called vessel elements or members.

The end walls of vessel elements are trans­verse or oblique (Fig. 6.13 B-C). They are often completely dissolved (Fig. 6.13 A). The condi­tion is called simple perforation plate.

In a few cases the end walls remain intact and pos­sess several pores in reticulate, scalariform or forminate forms. Such an end wall is called multiple perforation plate (Fig. 6.13 D), e.g., Liriodendron, Magnolia. Vessels help in quick movement of water in the plant.

The walls of the xylem vessels are lignified. They are thickened variously— annular, spiral, reticulate, scalariform and pitted. The pitted condition is more common. In outline the vessels are rounded in monocots and angular in dicots.

Vessels are absent in gym­ no-sperms and pteridophytes with the exceptions of a few (e.g., Selaginella species, Gnetum). Their tracheary elements comprise tracheids only. Flowering plants possess both vessels and tracheids but the latter are comparatively fewer.

(c) Xylem or Wood Parenchyma:

It is made of generally small thin or thick walled parenchymatous cells having simple pits. The wood parenchyma stores food (starch, fat) and sometimes tannins. It helps in the lateral conduction of water or sap. Ray parenchyma cells are specialised for this.

(d) Xylem or Wood Fibres:

They are sclerenchyma fibres associated with xylem. Xylem fibres are mainly mechanical in function. They are aseptate but can be septate.

Xylem fibres are of two types:

(i) Libriform Fibres. Typical fibres with thick walls having simple pits and obliterated central lumens,

Intermediate between fibres and tracheids having thin walls and pits with reduced borders.

Iii. Protoxylem and Metaxylem:

Depending upon the time of origin in relation to the growth of the plant organ, the xylem is of two types, protoxylem and metaxylem. Protoxylem (Gk. protos— first, xylem— wood) is the first formed xylem, where lignification begins before the completion of elongation.

It is made up of small tracheids and vessels which possess annular or spiral thickenings. They are capable of being stretched. The later formed xylem is described as metaxylem (Gk. meta— after, xylem— wood).

It consists of bigger tracheids and vessels which have reticulate, scalariform or pitted thickenings. Lignification occurs in them after completion of elongation. Depending upon the position of protoxylem in relation to metaxy­lem, xylem can be of four types— exarch, mesarch, centrarch and endarch.

In exarch (L. ex— without, Gk. arche— beginning) type, protoxylem lies towards the outside of metaxylem. It is inner in the endarch (Gk. endon— within, arche— beginning), middle of metaxylem in the mesarch xylem (Gk. mesos— middle, arche— beginning) and centre of metaxylem in centrarch xylem.

Protophloem and Metaphloem:

Protophloem is the first formed part of phloem which develops in parts that are under­going enlargement. It consists of narrow enucleate sieve elements which may occur singly or in groups amongst cells that often grow later into fibres. Companion cells may or may not be associated with protophloem. During elongation the protophloem elements (sieve elements) get stretched and become non-functional.

Metaphloem is part of primary phloem that differentiates in plant organs after they have stopped enlargement. The sieve elements are wider and longer. Companion cells are regularly associated. Fibres are absent but parenchyma cells may later become sclerified.

Antimicrobial Activities of African Medicinal Spices and Vegetables

2.3.3 Tannins

Tannins are polymeric phenolic substances possessing astringent property. These compounds are soluble in water, alcohol, and acetone and give precipitates with proteins ( Basri and Fan, 2005 ). Tannins are either hydrolyzable or condensed. Hydrolyzable tannins are based on gallic acid condensed tannins, often called proanthocyanidins are based on flavonoid monomers, flavones derivatives, or quinine units. Hydrolyzable and condensed tannins, derived from flavanols, exert antimicrobial activity via antiperoxidation properties, inhibiting particularly the growth of uropathogenic E. coli ( Okuda, 2005 ). Condensed tannins have been determined to bind cell walls of ruminal bacteria, preventing growth and protease activity ( Jones et al., 1994 ). Tannins in plants inhibit insect growth and disrupt digestive events in ruminal animals ( Cowan, 1999 ).