GLOSSARY

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Bract.


HAIRS

Trichomes
Trichomes are hairs or protuberances of various kinds on plants Some trichomes are hollow and needle-like, as in stinging nettles, where they actively inject some poisonous venom in mammalian skin. The trichomes in stinging nettles are made of hollow silica tubes so sharp as to be able to pierce skin at the slightest touch.

Other trichomes may be glandular hairs, some branched.

Glabrous
Lacking hairs or trichomes; a smooth surface.

Hirsute
Coarsely Hairy

Hispid
Having bristly hairs

Downy
Having an almost wool-like covering of long hairs

Pilose
Pubescent with long, straight, soft, spreading or erect hairs

Pubescent
Bearing hairs or trichomes of any type

Puberulent
Minutely pubescent; having fine, short, usually curly, hairs

Strigose
Having straight hairs all pointing in more or less the same direction as along a margin or midrib

Strigillose
Minutely strigose

Villous
Having long, soft hairs, often curved, but not matted

Tomentose
Covered with dense, matted, woolly hairs

Tomentellous
Minutely tomentose

Villosulous
Minutely villous Glandular Hairs
Those terminated by a tiny bobble (not those with a lump or a trichome at the base)


Stolons
The short-lived spreading stems by which some spreading plants propagate themselves. Stolons can be either above ground, or below ground. They produce roots at the nodes, which are distributed along the stolon.

Runners
The overground spreading 'stems' (or stolons) with which some plants use to propagate and spread to cover the ground. An example of a plant that spreads by way of Runners is Creeping Buttercup.


Herb
Herb has two definitions regarding plants.
Herb (1) A flowering plant whose stem does not go woody and where the aerial parts (those above ground level) usually die back at the end of the growing season. Hence the word 'herbaceous' used in gardening. They are not necessarily edible, indeed, some are deadly poisonous.
Herb (2) A plant whose aerial parts (or some of them) are used as spices or seasoning in cooking. Not a lot is used; herbs are not like vegetables or fruits. Indeed, some herbs, such as mint, may be slightly poisonous if eaten to excess, or even highly poisonous in the case of nutmeg where only a little is ever used in cooking.

Pappus Scale
The feathery part of the top of some seeds, on those plants with a Dandelion-type 'clock' (which can be minute).

Receptacular Scale
the minute casing around disc-florets on species of Asteraceae plants.

Apomixic / Apomictic
The production of viable seeds without self-fertilization or cross-fertilization and entirely female in origin. Apomixis is the process of apomictic reproduction. An apomict is a plant that regularly reproduces apomictically. Brambles (Rubus is one example, as are Hawkweeds (Hieracium) and Dandelions (Taraxacum), each of these Genera have hundreds of very similar species. Others are Hawthorns (Cratageous), Rowans and Whitebeams (Sorbus), Grasses (Poa).

Parthenogenesis
Some apomixis is parthenogenetic. Apomictic parthenogenesis occurs without meiosis and gives rise to full clones. An example of a parthenogenetic plant is Parthenocissus quinquefolia (Virginia-Creeper) and Parthenocissus tricuspidata (Boston Ivy).

Parthenocarpy
Virgin fruit. Fruit which is seedless, either naturally or induced artificially. Eaxamples of natural seedless fruit is Banana, Cucumber (if pollinators are excluded), some pineapple and some Pears. Others are artificially induced to grow without seeds, such as seedless Grape, seedless Watermelon, seedless Aubergine, seedless Tomato, etc.



Annual
Annuals have very short lives, surviving only for one season. If they grow again in the sane spot, it is because they have self-seeded themselves. Because of their short life-span they have much greater genetic diversity and often display highly variable characteristics, such as the shape of the leaves, etc. Because they reproduce every year (if they grow again) their propensity for genetic variation is increased. They usually have weak root systems and are easily uprooted, but this is not the way to tell if it is an annual if the plant is at all rare.

Biennial
Biennials are ....

Perennial
Perennials have a thick root system and are not easily uprooted. Think Dandelion. Perennials are ...