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The families of flowering plants

L. Watson and M.J. Dallwitz

Hypoxidaceae R. Br.

~ Amaryllidaceae, Liliaceae.

Habit and leaf form. Herbs. Perennial; with a basal aggregation of leaves; cormous, or rhizomatous. Mesophytic. Leaves alternate; mostly tristichous; sessile, or petiolate; sheathing. Leaf sheaths with free margins. Leaves ‘normally orientated’; simple; epulvinate. Lamina entire; linear, or lanceolate; parallel-veined, or pinnately veined (then parallel-pinnate); without cross-venules. Lamina margins entire. Leaf development presumably ‘graminaceous’. Vernation sometimes plicate.

Leaf anatomy. The leaf lamina dorsiventral. Stomata present; paracytic (usually), or paracytic and tetracytic (Curculigo). Hairs present, or absent; eglandular. Multicellular hairs branched, or simple. Complex hairs present, or absent; often stellate (or scales). Adaxial hypodermis absent. Lamina with secretory cavities, or without secretory cavities. Secretory cavities when present, containing mucilage. The mesophyll containing crystals. The crystals raphides. Foliar vessels absent. Minor leaf veins without phloem transfer cells (Rhodohypoxis).

Axial (stem, wood) anatomy. Secretory cavities present, or absent; when present, with mucilage. Secondary thickening absent. The axial xylem without vessels.

Root anatomy. Root xylem with vessels; vessel end-walls scalariform.

Reproductive type, pollination. Fertile flowers hermaphrodite. Plants hermaphrodite. Floral nectaries absent (nectaries lacking).

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; when aggregated, in racemes, or in spikes, or in heads, or in umbels. The ultimate inflorescence units racemose. Inflorescences scapiflorous; terminal; spikes, racemes or umbellate clusters; with involucral bracts, or without involucral bracts. Flowers regular; 3 merous; cyclic. Perigone tube present, or absent.

Perianth of ‘tepals’; 4, or 6; free, or joined; 2 whorled; isomerous; petaloid; similar in the two whorls; yellow, or white, or red (rarely); persistent (patent). Tepal apex trichomes (TAT) present (Hypoxis, Molineria, Pauridia, Rhodohypoxis).

Androecium 3 (rarely), or 4, or 6. Androecial members usually adnate (to the perianth); united with the gynoecium (more or less attached to the base of the style, in Curcilago), or free of the gynoecium; free of one another; 2 whorled (3+3). Androecium exclusively of fertile stamens. Stamens 3, or 4, or 6; isomerous with the perianth (usually), or reduced in number relative to the adjacent perianth. Anthers dorsifixed, or basifixed; dehiscing via longitudinal slits; introrse; tetrasporangiate. Endothecium developing fibrous thickenings. The endothecial thickenings spiral. Anther epidermis persistent. Microsporogenesis successive. Tapetum amoeboid. Pollen grains aperturate; 1 aperturate; sulcate; 2-celled.

Gynoecium 3 carpelled. The pistil 1 celled, or (2–)3 celled (usually). Gynoecium syncarpous; synovarious to synstylovarious; inferior. Ovary (2–)3 locular (usually), or 1 locular (Empodium). Styles 1, or 3; free to partially joined; apical. Stylar canal present. Stigmas dry type; papillate; Group II type. Placentation when unilocular (i.e. rarely), parietal; usually axile. Ovules arillate (sometimes, carunculate), or non-arillate; anatropous, or hemianatropous; bitegmic; tenuinucellate. Outer integument contributing to the micropyle. Embryo-sac development Polygonum-type, or Allium-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; proliferating (a little, occasionally, in Ianthe), or not proliferating; ephemeral. Synergids sometimes with filiform apparatus. Endosperm formation nuclear, or helobial. Endosperm haustoria present (at least in Curcilago and Hypoxis); chalazal. Embryogeny asterad.

Fruit fleshy, or non-fleshy; dehiscent (variously), or indehiscent; a capsule, or a berry. Capsules sometimes denticidal, or poricidal. Seeds copiously endospermic. Endosperm oily. Testa encrusted with phytomelan (always?); black, or brown.

Seedling. Hypocotyl internode absent. Mesocotyl absent. Seedling collar not conspicuous. Cotyledon hyperphyll compact; non-assimilatory. Coleoptile present. Seedling cataphylls absent. First leaf dorsiventral. Primary root ephemeral.

Physiology, phytochemistry. Accumulated starch other than exclusively ‘pteridophyte type’. Not cyanogenic. Alkaloids absent. Saponins/sapogenins seemingly absent. Proanthocyanidins absent. Flavonols present; quercetin. Ellagic acid absent.

Geography, cytology. Holarctic, Paleotropical, Neotropical, Cape, Australian, and Antarctic. Temperate to tropical. Widespread, but not in Europe or Northern Asia.

Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Liliiflorae; Asparagales. APG III core angiosperms; Superorder Lilianae; non-commelinid Monocot. APG IV Order Asparagales.

Species about 150. Genera 8; Curculigo, Empodium, Hypoxidia, Hypoxis, Molineria, Pauridia(?), Rhodohypoxis, Spiloxene.

Illustrations. • Le Maout and Decaisne: Hypoxis erecta, Curculigo. • Hypoxis obtusa: Bot. Reg. 2 (1816). • Hypoxis stellipilis: Bot. Reg. 8 (1822). • Molineria latifolia (as Curculigo): Bot. Mag. 46 (1818).

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: 15th April 2018.’.