Description:

• Perennial evergreen or deciduous herbs, rarely shrubs with anomalous secondary growth
• Rootstock a rhizome, corm, or when shrubs, a woody caudex
• Leaves basal and cauline, sometimes lower 2 or 3 without blades, sheathing stem base and reaching shortly above ground (thus cataphylls); mostly distichous, bases usually imbricate, sheaths of foliage leaves open or closed, usually contemporary with flowers, occasionally produced later, rarely already dry at flowering, occasionally leaves of flowering stem with reduced to entirely sheathing blades, then foliage leaves sometimes produced from separate shoots; blades either unifacial and oriented edgewise to stem, parallel-veined, without or with a distinct central vein, this sometimes thickened, surface plane, ribbed, plicate or occasionally terete; or bifacial and oriented with adaxial surface facing stem, then channelled to flat and usually without a median vein; margins plane or sometimes undulate to crisped, sometimes thickened and fibrotic or raised into wings held at right angles to surface
• Flowering stems aerial or subterranean, simple or branched, terete or compressed, then often angled or winged
• Inflorescence either composed of umbellate monochasial cymes (i.e. rhipidia) enclosed in opposed leafy to dry bracts (spathes) with flowers usually pedicellate, sometimes sessile, each flower within rhipidium subtended by one bract; or flowers sessile, subtended by a pair of opposed bracts and solitary or in a spike
• Flowers bisexual, with a petaloid perianth of 2 whorls of 3 tepals each, rarely inner whorl suppressed, actinomorphic or zygomorphic and then usually bilabiate, variously coloured, often with contrasting markings; scented or unscented
• Tepals usually large and showy, whorls equal or unequal, when zygomorphic, posterior tepal usually largest and inclined to hooded, lower three often smallest and with contrasting markings (nectar guides); free to base or united in a tube, tube straight or curved, cylindric or funnel- to trumpet-shaped
• Stamens 3, arising at base of outer tepals, or in tube, symmetrically disposed or unilateral and arcuate, or sometimes declinate; filaments filiform, free or partly to completely united; anthers 2-thecous, usually extrorse and dehiscing longitudinally, occasionally apically or basally dehiscent; pollen monosulcate, trisulcate, zonasulculate, dizonasulculate, spiraperturate or inaperturate, operculate or not, exine reticulate to areolate or micropunctate
• Ovary inferior, 3-locular with axile placentation (rarely 1-locular with parietal placentation); ovules anatropous or campylotropous, many to few, in 2 rows per locule, rarely in 1; style filiform, usually 3-branched, sometimes simple, or 3-lobed, style branches either filiform to distally expanded, sometimes each divided in upper half and stigmatic towards apices, or branches thickened or flattened and petaloid, stigmas then abaxial below apices
• Fruit a loculicidal capsule, rarely indehiscent, firm to cartilaginous, occasionally woody, xerochastic or rarely hygrochastic
• Seeds globose to angular or discoid, sometimes broadly winged, usually dry, rarely seed coat fleshy or an aril present, rugulose or smooth, shiny or matte; endosperm hard, with reserves of hemicellulose, oil and protein; embryo small

Classification Notes:

• The family is currently divided into four subfamilies (Goldblatt 1990), but tribal delimitations remain unsatisfactory. Subfamily Isophysidoideae is monotypic comprising the Tasmanian Isophysis T.Moore with a superior ovary. The remaining subfamilies, Nivenioideae, Iridoideae and Ixioideae are all represented in southern Africa

Nomenclature:

• Iridaceae
  • Goldblatt: 607 (1990)
  • Goldblatt: 1 (1991)
  • Chase et al.: 109 (1995)

Distribution & Notes:

• Global: Genera ± 70. species 1 800, nearly worldwide, but rare in tropical lowlands; best represented in southern Africa
• Southern Africa: Genera 32, species 1 020

Notes:

• Iridaceae are of considerable economic importance in horticulture and cut-flower industry, especially Iris, Gladiolus and Freesia
• Several other genera (Dietes, Crocus, Watsonia) are cultivated in gardens in both tropical and temperate areas
• Many species of Moraea are poisonous and cause significant losses in cattle- and sheep-raising areas
• Some genera are of importance in traditional medicine, especially Gladiolus
• Corms of several species of Lapeirousia and a few of Moraea are eaten locally. The corms of these and genera such as Freesia, Gladiolus, and Watsonia were an important source of food for humans in prehistoric time and are a valued dietary supplement in some rural communities today

References:

• CHASE, M.W., DUVALL, M.R., HILLS, H.G., CONRAN, J.G., COX, A.V., EGUIARTE, L.E., HARTWELL, J., FAY, M.F., CADDICK, L.R., CAMERON, K.M. & HOOT, S. 1995. Molecular phylogenetics of Lilianae. In P.J. Rudall, P.J. Cribb, D.F. Cutler & C.J. Humphries (eds.). Monocotyledons: systematics and evolution. Royal Botanic Gardens, Kew
• GOLDBLATT, P. 1990. Phylogeny and classification of Iridaceae. Annals of the Missouri Botanical Garden 77
• GOLDBLATT, P. 1991. An overview of the systematics, phylogeny and biology of the southern African Iridaceae. Contributions from the Bolus Herbarium 13

Resources:

• Classification of Iridaceae
• Key to Iridaceae genera

• Iridaceae genera: