Family Restionaceae
Restionaceae R. Br.Excluding Anarthriaceae, Ecdeiocoleaceae Habit and leaf form. Xeromorphic herbs. ‘Normal’ plants to switch-plants, or plants of very peculiar vegetative form (female Alexgeorgia being almost subterranean); commonly with the principal photosynthesizing function transferred to stems. Leaves well developed, or much reduced (the blade being usually much reduced or absent). Plants with roots. Perennial; with a basal aggregation of leaves, or with neither basal nor terminal aggregations of leaves. Young stems not breaking easily at the nodes. Rhizomatous. Self supporting, or climbing; sometimes scrambling. Xerophytic. Leaves evergreen, or deciduous; alternate; distichous (usually), or spiral; leathery, or membranous; sessile; sheathing (and generally more or less reduced to the sheaths). Leaf sheaths with free margins. Leaves simple. Lamina when present, entire; when present, parallel-veined; without cross-venules. Leaves ligulate, or eligulate; stipulate (in the form of membranous lobes at the tops of the sheath margins), or exstipulate; with a persistent basal meristem, and basipetal development (?). General anatomy. Plants with silica bodies (commonly, usually in the bundle sheaths), or without silica bodies. Chlorenchyma including ‘peg cells’. Accumulated starch exclusively ‘pteridophyte type’. Leaf anatomy. Epidermis conspicuously differentiated into ‘long’ and ‘short’ cells, or without differentiation into ‘long’ and ‘short’ cells; containing silica bodies (e.g. Lepyrodia, Thamnochortus), or without silica bodies. Stomata present, or absent; paracytic. Guard-cells variously not ‘grass type’, or ‘grass type’. The mesophyll not containing mucilage cells; usually without calcium oxalate crystals (and no raphides). Vessels absent (from 19 genera sampled). Stem anatomy. Stems with solid internodes, or with spongy internodes, or with hollow internodes. Young stems cylindrical, or tetragonal, or flattened, or oval in section (or polyhedral). Secondary thickening absent. Xylem with vessels. Vessel end-walls reticulately perforated, or scalariform, or scalariform and simple, or simple (and rhizomes with exclusively simple perforation plates?). Sieve-tube plastids P-type; type II. Root anatomy. Root xylem with vessels; vessel end-walls scalariform (in the 4 genera recorded). Reproductive type, pollination. Plants dioecious (usually), or hermaphrodite, or monoecious. Female flowers with staminodes, or without staminodes. Gynoecium of male flowers vestigial, or absent. Floral nectaries absent (nectaries absent). Pollination anemophilous. Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in ‘spikelets’ (often), or not in ‘spikelets’. Inflorescences scapiflorous, or not scapiflorous; terminal; spikelike panicles, often compound, sometimes sexually dimorphic, sometimes with flowers aggregated in ‘spikelets’. Flowers bracteate; bracteolate (sometimes with one or two bracteoles), or ebracteolate; minute, or small; regular, or somewhat irregular; cyclic; tetracyclic. Perigone tube absent. Perianth of ‘tepals’, or vestigial, or absent; members (3–)6; free (usually), or joined (the inner members sometimes basally connate); 2 whorled (usually), or 1 whorled (the inner whorl sometimes missing); isomerous, or anisomerous (the inner whorl, when present, sometimes reduced in number); if anything, sepaloid; similar in the two whorls. Androecium (1–)2, or 3. Androecial members free of the perianth; free of one another, or coherent; sometimes 1 adelphous; 1 whorled. Androecium exclusively of fertile stamens. Stamens (1–)2, or 3; reduced in number relative to the adjacent perianth, or isomerous with the perianth; oppositiperianthial (opposite the inner perianth members). Anthers dorsifixed, or basifixed; versatile, or non-versatile; dehiscing via longitudinal slits; introrse, or latrorse; bisporangiate, or tetrasporangiate; appendaged (via the apex of the connective), or unappendaged. Endothecium developing fibrous thickenings. Anther epidermis persistent. Anther wall initially with one middle layer. Tapetum glandular (?). Pollen shed as single grains. Pollen grains aperturate; 1 aperturate; ulcerate. The ulcus without an operculum (or the operculum vestigial, represented by coarse granules or exine fragments); with an annulus, or without an annulus. Interapertural exine scrobiculate. Interapertural interstitium columellate. Pollen grains 2-celled (?), or 3-celled (in Hypodiscus). Gynoecium (1–)3 carpelled. Carpels isomerous with the perianth, or reduced in number relative to the perianth. The pistil 1–3 celled. Gynoecium monomerous (rarely), or syncarpous; of one carpel (rarely), or synovarious, or synstylovarious; superior. Carpel stylate; apically stigmatic; when G1, 1 ovuled. Placentation when G1, apical to marginal. Ovary 1–3 locular; sessile to stipitate. Gynoecium stylate. Styles (1–)3; free, or partially joined. Placentation when plurilocular, axile to apical. Ovules in the single cavity (when unilocular) 1; (when plurilocular) 1 per locule; funicled, or sessile; pendulous; non-arillate; orthotropous; bitegmic; tenuinucellate. Outer integument contributing to the micropyle. Embryo-sac development Polygonum-type (sometimes the ‘Poaceae variant’). Antipodal cells formed; 3; proliferating (in some genera, e.g. Elegia, Restio, Thamnochortus), or not proliferating; usually ephemeral. Synergids pear-shaped, or hooked (sometimes with filiform apparatus); non-haustorial. Hypostase present, or absent. Endosperm formation nuclear. Fruit non-fleshy. The fruiting carpel when G1, indehiscent; nucular. Fruit (when syncarpous, as is usual) dehiscent, or indehiscent; a capsule, or a nut. Capsules when dehiscent, loculicidal. Fruit 1–3 seeded. Seeds copiously endospermic. Embryo weakly differentiated (? — small, lenticular or obovate). Testa without phytomelan (always?). Seedling. Hypocotyl internode absent. Seedling collar not conspicuous. Cotyledon hyperphyll elongated; assimilatory; more or less circular in t.s. Coleoptile absent. Seedling cataphylls absent. First leaf centric. Primary root ephemeral. Physiology, biochemistry. Not cyanogenic. Proanthocyanidins commonly present (and predominant in S. African material); cyanidin. Flavonols present (commoner in S. African species), or absent; kaempferol, quercetin, and myricetin (see Williams et al. (1998) and references therein for recently acquired information on flavonoid patterns in the family). Ellagic acid absent. Geography, cytology. Temperate (warm), or sub-tropical to tropical. Mostly South Africa and Australia, a few in New Zealand, Madagascar, Indochina and Chile. X = 7, 8, 8, 11, 12, 13. Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Commeliniflorae; Poales. APG 3 core angiosperms; Superorder Lilianae; commelinid Monocot; Order Poales. Species 320. Genera about 35; Alexgeorgia, Anthochortus, Askidiosperma, Calopsis, Cannomois, Ceratocaryum, Chaetanthus, Chondropetalum, Coleocarya, Dielsia, Dovea, Elegia, Empodisma, Harperia, Hopkinsia, Hydrophilus, Hypodiscus, Hypolaena, Ischyrolepis, Lepidobolus, Leptocarpus, Lepyrodia, Loxocarya, Lyginia, Mastersiella, Meeboldina, Nevillea, Onychosepalum, Platycaulos, Restio, Rhodocoma, Sporadanthus, Staberoha, Thamnochortus, Willdenowia, Winifredia. Illustrations. |
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