Ixia L.
Sp.Pl. p51 (1763)

Name Status: Current
Browse to the list of specimens for Ixia L.

Scientific Description
J. Gathe, Thursday 8 September 2016

Common name. Ixias. Family Iridaceae.

Habit and leaf form. Herbs (small); evergreen, or deciduous. Perennial (annual leaves and flowers). Leaves basal and cauline (mostly basal). Plants with a basal concentration of leaves, or with neither basal nor terminal concentrations of leaves; cormous (small, more or less globose to ovoid; tunic fibrous and reticulated). Helophytic to xerophytic. Leaves alternate; spiral, or distichous; ‘herbaceous’, or leathery; sessile; sheathing. Leaf sheaths with free margins. Leaves foetid, or without marked odour; edgewise to the stem, or with ‘normal’ orientation; simple; epulvinate. Leaf blades entire; flat; linear, or lanceolate; narrowly elliptic, or linear (to ensiform or filiform); parallel-veined (prominent); without cross-venules; open or closed sheaths. Leaves eligulate; without stipules. Leaf blade margins entire. Leaves with a persistent basal meristem, and basipetal development. Leaf anatomy. Hairs absent. Extra-floral nectaries absent. Stem anatomy. Secondary thickening absent.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Floral nectaries present, or absent. Nectar secretion from the gynoecium (septal nectaries). Entomophilous, or ornithophilous, or anemophilous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in spikes (or spike-like). The terminal inflorescence unit cymose, or racemose. Inflorescences terminal; scape erect, slender, wiry, simple or sometimes branched; inflorescence few to many-flowered, unbranched and spike-like or branched; spatheate (2 per rhipidium;). Flowers sessile; bracteate (2 per flower, spathe-like, subequal, inserted at the base of the ovary, persistent, oblong to obovate, truncate, shortly dentate, scarious or membranous, usually translucent and colourless but sometimes dry opaque and brown; outer bract shortly bifid or trifid; inner bract shortly divided). Bracts persistent. Flowers ebracteolate; small to large; regular (almost always), or very irregular; when irregular, zygomorphic; 3 merous; cyclic; tetracyclic. Perigone tube present. Perianth of ‘tepals’; 6; 2 -whorled; isomerous; petaloid; without spots, or spotted; similar in the two whorls, or different in the two whorls; white, or cream, or yellow, or orange, or blue (or mauve). Androecial members definite in number. Androecium 3. Androecial members adnate; all equal; free of one another (usually), or coherent (sometimes partly connate); when united, 1 - adelphous; 1 -whorled (representing the outer whorl). Androecium exclusively of fertile stamens. Stamens 3; all more or less similar in shape; reduced in number relative to the adjacent perianth to isomerous with the perianth; on the perianth tube opposite the outer segments; alterniperianthial (opposite the outer perianth lobes). Anthers basifixed; dehiscing via longitudinal slits; extrorse. Gynoecium 3 carpelled. The pistil 3 celled. Gynoecium partly petaloid, or non-petaloid; syncarpous; synstylovarious; inferior. Ovary plurilocular; 3 locular. The ‘odd’ carpel anterior. Gynoecium stylate. Styles 1; apical. Stigmas 3. Placentation axile. Ovules 20–50 per locule (many); arillate, or non-arillate; anatropous.

Fruit and seed features. Fruit thin-walled; dehiscent; a capsule. Capsules loculicidal (from the apex). Fruit 3 celled; 20–100 seeded (many). Seeds endospermic. Endosperm oily. Cotyledons 1 (coleoptile-like). Embryo straight (small). Testa without phytomelan.

Etymology. From the Greek for "a plant of variable colouring".

Taxonomic Literature

  • Wheeler, Judy; Marchant, Neville; Lewington, Margaret; Graham, Lorraine (2002). Flora of the south west, Bunbury, Augusta, Denmark. Volume 1, introduction, keys, ferns to monocotyledons. Australian Biological Resources Study. Canberra.
  • Australia. Bureau of Flora and Fauna (1986). Flora of Australia. Volume 46, Iridaceae to Dioscoreaceae. Australian Govt. Pub. Service. Canberra.