| | The Families of Angiosperms |
Excluding Anarthriaceae, Centrolepidaceae, Ecdeiocoleaceae.
Habit and leaf form. Xeromorphic herbs. ‘Normal’ plants to switch-plants, or plants of very peculiar vegetative form (e.g., 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). Perennial; with a basal aggregation of leaves, or without conspicuous aggregations of leaves. Young stems not breaking easily at the nodes. Rhizomatous. Self supporting, or climbing; sometimes scrambling. Xerophytic. Leaves persistent, 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 (via membranous lobes at the tops of the sheath margins), or exstipulate; leaf development ‘graminaceous’ (?).
General anatomy. Plants with silica bodies (commonly, usually in the bundle sheaths), or without silica bodies. Chlorenchyma including ‘peg cells’.
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 crystals (and no raphides). Foliar vessels absent (from 19 genera sampled).
Axial (stem, wood) anatomy. Young stems cylindrical, or tetragonal in section, or flattened, or oval in section (or polyhedral); with solid internodes, or with spongy internodes, or with hollow internodes. Secondary thickening absent.
The vessel end-walls reticulately perforated, or scalariform, or scalariform and simple, or simple (and rhizomes with exclusively simple perforation plates?).
Root anatomy. Root xylem with vessels; vessel end-walls scalariform (in the 4 genera recorded).
Reproductive type, pollination. Unisexual flowers present, or absent. 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, when present, (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, phytochemistry. Accumulated starch exclusively ‘pteridophyte type’. 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. Sieve-tube plastids P-type; type II.
Geography, cytology. Temperate (warm), 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 III core angiosperms; Superorder Lilianae; commelinid Monocot. APG IV Order Poales.
Species 320. Genera about 35; Alexgeorgia, Anthochortus, Askidiosperma, Baloskion, 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. • Le Maout and Decaisne: Baloskion tetraphyllum, as Restio. • Calopsis paniculata, Cannomois virgata (as C. cephalotes) and Thamnochortus lucens (as Restio dichotomus): Rottboell, Descriptionum et iconum rariores (1773). • Hypolaena fastigiata: J.D. Hooker, Fl. Tasmaniae (1860). • Lepyrodia hermaphrodita, Restio dichotomus: Lindley. • Apodasmia brownii (as Leptocarpus): Hooker, Fl. Tasmaniae (1860). • Restio compressus: Thonner.
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 19th May 2024. delta-intkey.com’.
