Family Alliaceae
General anatomy. Plants with laticifers (articulated), or without laticifers. The laticifers of Allium, in leaves (in the inner chlorenchyma). Leaf anatomy. Stomata present; anomocytic. The mesophyll containing calcium oxalate crystals, or without calcium oxalate crystals (? — ‘raphides sometimes present, sometimes absent’). Minor leaf veins without phloem transfer cells (Allium, Triteleia). Stem anatomy. Secondary thickening absent. Xylem without vessels. Sieve-tube plastids P-type; type II. Root anatomy. Root xylem with vessels; vessel end-walls scalariform and simple (mainly simple, by contrast with Amaryllidaceae). Reproductive type, pollination. Plants hermaphrodite. Floral nectaries present. Nectar secretion from the gynoecium (from septal nectaries). Pollination entomophilous. Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’ (usually), or solitary (Ipheion); in umbels. The ultimate inflorescence unit cymose. Inflorescences scapiflorous; umbellate, usually representing one or more contracted, helicoid cymes; with involucral bracts (the umbel surrounded by (1–)2(to several) bracts, which may be fused); spatheate (with reference to the one to several spathal involucral bracts). Flowers fragrant, or odourless; regular to somewhat irregular. The floral irregularity e.g. in some Allium species, involving the androecium. Flowers 3 merous; cyclic; pentacyclic. Perigone tube present, or absent. Perianth of ‘tepals’; 6; free to joined; 2 whorled (3+3); isomerous; petaloid; similar in the two whorls; white, or violet, or blue, or purple, or yellow, or green and white, or brown and white, or white and red. Androecium 6. Androecial members adnate (at the base of the tepals, or to the tube); all equal (mostly), or markedly unequal (Ipheion); free of one another (mostly), or coherent (the filaments sometimes basally cohering in Allium); 2 whorled (3+3). Androecium exclusively of fertile stamens (usually), or including staminodes. Staminodes when present, 3, or 4. Stamens 6 (usually), or 2–3 (e.g. the Gilliesia group, Leucocoryne); isomerous with the perianth (usually), or reduced in number relative to the adjacent perianth; alterniperianthial, or oppositiperianthial (sometimes even when six-stamened — e.g. see Dahlgren et al. 1985, drawings of Tritagma, p. 197); filantherous (the filaments flat). Filaments appendiculate, or not appendiculate. Anthers dorsifixed; dehiscing via longitudinal slits; introrse. Endothecium developing fibrous thickenings. The endothecial thickenings spiral. Microsporogenesis successive. Tapetum glandular. Pollen grains aperturate; 1 aperturate; sulcate; 2-celled. Gynoecium 3 carpelled. Carpels isomerous with the perianth. The pistil 3 celled. Gynoecium syncarpous; synstylovarious, or eu-syncarpous; superior. Ovary 3 locular. Gynoecium stylate. Styles 1; almost ‘gynobasic’, or apical. Stylar canal absent (mostly), or present (‘Themidaceae’, Agapanthus). Stigmas wet type, or dry type; papillate. Placentation axile. Ovules 1–50 per locule (to ‘many’); campylotropous (usually), or anatropous (e.g. most ‘Themidaceae’); tenuinucellate (mostly), or crassinucellate (e.g. Agapanthus). Embryo-sac development Polygonum-type, or Allium-type. Antipodal cells formed; 3; not proliferating; ephemeral. Hypostase present. Endosperm formation nuclear, or helobial. Fruit non-fleshy; dehiscent; a capsule. Seeds endospermic. Endosperm oily. Seeds winged (e.g., Agapanthus), or wingless. Seeds without starch. Cotyledons 1. Embryo achlorophyllous (2/5); straight to curved. Testa encrusted with phytomelan; black. Seedling. Hypocotyl internode absent. Seedling collar not conspicuous. Cotyledon hyperphyll elongated (mostly), or compact; assimilatory (mostly), or non-assimilatory (e.g. in some Allium species); when elongated, more or less circular in t.s. Coleoptile absent. Seedling cataphylls present, or absent. First leaf centric, or dorsiventral. Primary root ephemeral. Physiology, biochemistry. Cyanogenic (?), or not cyanogenic. Alkaloids absent. Proanthocyanidins absent (12 species). Flavonols present (mostly), or absent (e.g. Agapanthus); kaempferol, or kaempferol and quercetin. Ellagic acid absent. Saponins/sapogenins present. Inulin recorded (Allium, Gibbs 1974). C3. C3 physiology recorded directly in Allium. Anatomy non-C4 type (Allium). Geography, cytology. Holarctic, Paleotropical, and Neotropical. Temperate, sub-tropical, and tropical. Cosmopolitan, but few in Australasia. Taxonomy. Subclass Monocotyledonae. Superorder Liliiflorae; Asparagales. APG (1998) Monocot; non-commelinoid. APG 3 (2009) Order: Asparagales. Species 600. Genera 30 (according to Dahlgren et al. 1985, who do not list them all); Agapanthus, Allium, Ancrumia, Androstephium, Behria, Bessera, Bloomeria, Brodiaea, Dandya, Dichellostemma, Diphalangium, Erinna, Garaventia, Gethyum, Gilliesia, Ipheion, Leucocoryne, Miersia, Milla, Milula, Nectaroscordum, Nothoscordum, Milla, Muilla, Pabellonia, Petronymphe, Schickendantziella, Solaria, Speea, Trichlora, Tristagma, Triteleia, Triteleiopsis, Tulbaghia, Zoellnerallium. Fay and Chase (1996) resurrect Themidaceae and transfer Agapanthus to Amaryllidaceae, on the basis of rbcL DNA sequencing. These proposals have not yet been implemented here. Economic uses, etc. Allium spp. supply onions and garlic. |
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