Family Hypoxidaceae

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 with ‘normal’ orientation; simple; epulvinate. Lamina entire; linear, or lanceolate; parallel-veined, or pinnately veined (then parallel-pinnate); without cross-venules. Lamina margins entire. Leaves with a persistent basal meristem, and basipetal development. Vernation sometimes plicate.

General anatomy. Accumulated starch other than exclusively ‘pteridophyte type’.

Leaf anatomy. Stomata present; paracytic (usually), or paracytic and tetracytic (Curculigo). Hairs present, or absent; eglandular. Multicellular hairs branched, or unbranched. Complex hairs present, or absent; often stellate (or scales).

Adaxial hypodermis absent. Lamina dorsiventral; with secretory cavities, or without secretory cavities. Secretory cavities when present, containing mucilage. The mesophyll containing calcium oxalate crystals. The mesophyll crystals raphides. Minor leaf veins without phloem transfer cells (Rhodohypoxis). Vessels absent.

Stem anatomy. Secretory cavities present, or absent; when present, with mucilage. Secondary thickening absent. 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’; in racemes, in spikes, in heads, and in umbels. The ultimate inflorescence unit 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).

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, biochemistry. Not cyanogenic. Alkaloids absent. Proanthocyanidins absent. Flavonols present; quercetin. Ellagic acid absent. Saponins/sapogenins seemingly 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 3 core angiosperms; Superorder Lilianae; non-commelinid Monocot; Order Asparagales.

Species about 150. Genera 7; Curculigo, Empodium, Hypoxidia, Hypoxis, Pauridia(?), Rhodohypoxis, Spiloxene.

Illustrations.
• Technical details: Hypoxis, Curculigo.