Webbs An Irish Flora

GLOSSARY OF TECHNICAL TERMS

439 Achene A dry, indehiscent, one-seeded fruit with a membranous pericarp . Alien A plant that has been accidentally or deliberately introduced to Ireland through human activity. Alternate Arising singly, not in pairs or whorls [Gloss. Fig. 1]. Andromonoecious Having hermaphrodite and male flowers on the same plant. Annual A plant that grows from seed, flowers and dies, all within a period of twelve months. Anther The upper part of a stamen, in which the pollen is produced [Gloss. Fig. 2]. Apomictic Reproducing asexually, including vegetative reproduction, and the production of seed that has no male genetic component . Aril An extra coat, usually rather fleshy, found on certain seeds, outside the normal seed-coat. Auricle One of the projecting lobes at either side of the base of a cordate, sagittate or stem-clasping leaf [Gloss. Fig. 3]. Awn A long, bristle-like point, commonly borne by the glumes or lemmas of certain grasses, e.g. Barley [Gloss. Fig. 4]. Axil The angle between a leaf and the stem just above its point of attachment. Each axil normally contains a shoot or a bud. Axillary Arising from, or situated in the axil of a leaf. Basal Refers to leaves arising from the extreme base of the stem. Berry A fleshy fruit, usually rather small, containing one or more seeds in a pericarp that is entirely succulent. Biennial A plant that normally lives for about two years, producing leaves and often a stout root the first year; it typically flowers in its second year and then dies. Bifid Deeply divided, usually lengthwise, into two. Biternate A ternate leaf in which the divisions are themselves ternate. Bract A leaf, usually smaller and often different in shape or texture from the foliage leaves, which is closely associated with a flower or inflorescence. Bracts may be solitary, or grouped together in an involucre. In the Apiaceae the segments of the GLOSSARY OF TECHNICAL TERMS involucre, if present, at the base of the general umbel are called bracts; those, if present, at the base of the partial umbels are called bracteoles. Bracteole A small bract at the base of a single flower in a compound inflorescence; and especially one at the base of a partial umbel in a member of the Apiaceae [Gloss. Fig. 5]. Bud A growing point: normally the apex of the shoot together with a series of scales, which closely cover it; sometimes these scales are absent and the apex itself is hairy. Calyx The sepals, considered as a whole, whether free or united, forming the outermost whorl of floral parts [Gloss. Fig. 2]. Capillary Of leaves that are so finely divided they appear hair-like. Capsule A dry, dehiscent fruit, formed from two or more carpels, usually containing numerous seeds. Carpel The female reproductive unit, consisting of an ovary, style and stigma. Sometimes each flower has a single carpel; more often there are two or more, which may be quite free from each other or wholly or partly fused together [Gloss. Fig. 2]. Caryopsis Effectively the seed of a grass (Poaceae), comprising a fruit with the ovary-wall and seed-coat united. Catkin A type of inflorescence characteristic of various families, including the Willows. It is typically a cylindrical spike, ultimately falling as a whole, made up of numerous, small unisexual flowers, with an inconspicuous perianth or none, arranged singly or in small groups in the axils of usually crowded and overlapping scale-like bracts. Chromosome The molecule that contains the genetic code of all living organisms, both plant and animal, is DNA (deoxyribose nucleic acid). These molecules are assembled into chromosomes, which are visible, after staining, under the microscope. Cleistogamous Of flowers which never fully open but which still have the capacity to produce seeds through self-pollination. Cordate Notched or indented at the base, where the stalk is attached [Gloss. Fig. 6]. Corm A storage organ, found in the Crocus, Gladiolus, etc., looking superficially like a bulb, but consisting of a swollen stem-base instead of swollen leaves. GLOSSARY OF TECHNICAL TERMS 440 GLOSSARY OF TECHNICAL TERMS 441 Spikelet expanded Glos. Fig. 1 Glos. Fig. 2 Glos. Fig. 5 Glos. Fig. 6 Glos. Fig. 7 Glos. Fig. 3 144444444444444444444443 Glos. Fig. 4 GLOSSARY OF TECHNICAL TERMS 442 Glos. Fig. 8 Glos. Fig. 9 Glos. Fig.10 Glos. Fig.11 Glos. Fig. 12 Glos. Fig. 13 Glos. Fig.14 Glos. Fig.15 Glos. Fig. 16 144444444444444444444443 Glos. Fig. 17...