Perennial evergreen or deciduous herbs, occasionally shrubs with anomalous secondary growth (Klattia, Nivenia, Witsenia), rarely annuals (Sisyrinchium spp.), or an achlorophyllous saprophyte (Geosiris). Rootstock a rhizome, corm or bulb, or, when shrubs, a woody caudex or rootstock indistinct. Leaves basal and cauline, sometimes the lower 2-3 without blades, sheathing the stem base and reaching shortly above the ground (thus cataphylls), mostly distichous, the bases usually imbricate, sheaths of foliage leaves open or closed, usually contemporary with the flowers, occasionally produced later, rarely already dry at flowering, occasionally the leaves of the flowering stem with reduced to entirely sheathing blades, then foliage leaves sometimes produced from separate shoots; the blades either unifacial and oriented edgewise to the stem, parallel-veined, without or with a distinct central vein, this sometimes thickened, the surface plane, ribbed, plicate or occasionally terete, very rarely pseudopetiolate, narrow below and abruptly expanded above, or bifacial and oriented with the adaxial surface facing the stem, then channelled to flat and without a median vein; margins sometimes undulate to crisped, or thickened and fibrotic or raised into wings held at right angles to the surface; leaves achlorophyllous and scalelike in Geosiris. Flowering stems aerial or subterranean at anthesis, then emerging in fruit, simple or branched, terete or compressed, then often angled or winged, occasionally pubescent. Inflorescence either composed of I-many umbellate monochasial cymes (i.e. rhipidia) (Nivenioideae, Iridoideae) arranged in panicles or spikes or variously clustered terminally or on short lateral branches, the rhipidia paired and partly fused in Nivenioideae; rhipidia comprising pedicellate, occasionally subsessile, flowers each subtended by a single bract, enclosed, usually until anthesis, in large opposed sheathing bracts (spathes), the rhipidia occasionally solitary flowered; or a spike ofsessile flowers subtended by opposed bracts (Ixioideae), sometimes reduced to a single flower (e.g., Romulea, Xenoscapa), the inner (adaxial) bract forked apically and usually smaller, sometimes deeply divided, occasionally to the base (Babiana spp.). Flowers hermaphrodite, usually large and showy, with a petaloid perianth of 2 whorls of 3 tepals each, rarely the inner whorl suppressed, actinomorphic or zygomorphic (many Ixioideae), then usually bilabiate, the posterior tepal usually largest and inclined to hooded, the lower 3 often smallest, variously coloured, often with contrasting markings, when bilabiate the lower tepals marked with nectar guides; perianth of 6 petaloid tepals in 2 equal or more or less strongly different whorls, occasionally inner whorl reduced or lacking (especially Patersonia), tepals free to the base (most Iridodeae) or united in a tube (Nivenioideae, Ixioideae), the tube straight or curved, cylindric or funnel- to trumpet-shaped; nectaries septal (Ixioideae, Nivenioideae), perigonal (Iridoideae), on the base of the outer tepals (most Old World spp.) or the inner tepals (New World spp.) or nectaries lacking (e.g. most Aristea, Isophysis); oil glands (elaiophores) often present on the inner tepals on New World Iridoideae. Stamens 3 (2 in the Australian Diplarrhena), inserted at the base of the outer tepals, or in the tube, symmetrically disposed or unilateral and arcuate, or sometimes declinate; filaments filiform, free or partly to completely united, threadlike and not supporting the anthers in some New World genera; anthers basifixed to sub-basifixed or centrifixed, occasionally sagittate or versatile, 2-thecate, 4-sporangiate, extrorse to latrorse, opening by longitudinal slits, occasionally apically dehiscent. Gynoecium of 3 united carpels. Ovary inferior (but superior in the Tasmanian Isophysis) , 3-locular with axile placentation, rarely I-locular with parietal placentation (Hermodactylis); ovules anatropous or campylotropous, many to few, especially numerous and small in Geosiris, in 2 rows per locule, rarely in 1 row (Aristea); style terminal, filiform, usually 3-branched above, or 3-lobed, rarely simple (Zygotritonia), the style branches either filiform to distally expanded, sometimes each divided in the upper half, stigmatic towards the apices, or the branches thickened or flattened and petaloid, the stigmas then abaxial below the apices. Fruit a loculicidal capsule, rarely indehiscent, firm to cartilaginous, occasionally woody, xerochastic or rarely hygrochastic. Seeds often large, globose to angular or discoid, sometimes broadly winged, usually dry, brown, occasionally blackish, rarely the seed coat fleshy or an aril present, rugulose or smooth, shiny or mat; endosperm hard, with reserves of hemicellulose, oil and protein, rarely also starch; embryo small.
A family comprising ca. 70 genera and 1750 spp., cosmopolitan in distribution, but most abundant and diversified in southern Africa. More than 1/2 the species belonging to only 6 genera: Gladiolus (255), Iris (ca. 225), Moraea (200), Romulea (90), Geissorhiza (85), Crocus (80), and Sisyrinchium (ca. 80). These as well as Freesia (15), Ixia (45), Sparaxis (13), and Tigridia (ca. 30) are well known as ornamentals.
Goldblatt, P., Manning, J.C., Rudall, P.J., Kubitzki, K., 1998. Iridaceae With kind permission from Springer Science+Business Media: This work is subject to copyright. All rights reserved, whether whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, broadcasting reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer-Verlag. Violations are liable for prosecution under German Copyright Law.