Description

Key Characters:

Growth Form: Evergreen or seasonal, geophytic perennial herbs; or sometimes annual herbs (Sisyrinchium) or evergreen woody shrubs with secondary growth (Klattia Baker, Nivenia Venten. and Witsenia Thunb.).

Stems: Rhizomes, tunicate bulbs, or corms, flowering stems aerial or partly to entirely subterranean at anthesis in some genera, terete (cylindrical), angled, or winged, often branched.

Roots: Fibrous root system.

Leaves: Leaves simple. Usually distichous, usually isobilateral and unifacial. Blades usually equitant and ensiform (bifacial, terete (cylindrical), or square in some old world genera), blades flat or plicate. Margins entire. Veins parallel. Sessile and sheathing with closed or open sheathing base. Stipules absent.

Flowers: Flowers arranged in inflorescences either comprising several to few clusters each consisting of a pair of large, opposed, spathe-like bracts enclosing pedicellate flowers exserted serially, or spikes or panicles of sessile flowers (in Old World Ixioideae). Flowers usually large and showy, bisexual (perfect), actinomorphic or zygomorphic. Perianth of 6 petaloid tepals in 2 whorls, all alike, or the 2 whorls differentiated, occasionally the inner whorl absent, distinct (most Iridoideae) or connate below into a tube; nectaries often present, on the tepals (Iridoideae) or septal (Ixioideae). Stamens (2)3, opposite the outer tepals; filaments inserted at base of tepals or on perianth tube, sometimes connate basally or entirely into a tube; anthers basifixed to subbasifixed and often sagittate, dithecal, extrorse, opening by longitudinal slits or rarely by apical pores. Ovary usually inferior, 3-carpellate, 3-celled; ovules numerous to few (occasionally 1–2) per cell placentation axile (1-celled with parietal placentation in Hermodactylus Mill.); style 3-lobed or 3–branched, the branches sometimes again divided or expanded and petaloid; stigma on the abaxial surface of branches below apex (many Iridoideae).

Fruit: Loculicidal capsules; sometimes indehiscent. Seeds often large; usually brown to black or red; globose to angular (winged in some Old World genera); seed coat reticulate to smooth; sometimes fleshy (arillate in some Old World genera); endosperm hard; with reserves of hemicellulose; protein; and oil.

Ploidy:

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