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Iridaceae


This is a large family found almost throughout the world. In Australia it is a southern, temperate family, being absent from the arid centre and the tropical north (with the exception of one species of Patersonia found in the Top End of the Northern Territory). Most species are found in open vegetation from heathlands and heathy forests to alpine grasslands. Many introduced species are weeds of roadsides.

Characteristic features of the family Iridaceae in Australia include:

  • perennial herbs with swollen, sometimes bulb-like rootstocks and linear (rarely terete) sword-shaped leaves often arranged in two rows and flattened into one plane
  • flowers often showy, usually in branched inflorescences with each flower subtended by a dry, papery bract
  • perianth segments 6, usually petal-like and all similar or in 2 dissimilar whorls of 3 parts each, more or less fused into a tube at the base, regular or zygomorphic
  • stamens 3
  • ovary inferior (except in the Tasmanian Isophysis) with 3 style branches (which are sometimes petaloid), developing into a capsule with large seeds

Description

Annual or perennial terrestrial herbs, rarely evergreen shrubs. Perennating by corms or rhizomes, rarely by bulbs. Vegetative reproduction by corms, rhizomes or rarely bulbs, or by proliferous flowerheads. Leaves sometimes ±absent. Stem internodes spongy or pithy or hollow, terete or oval or slightly flattened. Internal secretions not obvious or rarely of mucilage. Plants glabrous, or with simple or dendritic, non-glandular, uniseriate hairs. Leaves distichous, all or mostly basal or both basal and cauline if herbs, subsessile or sessile. Stipule-like lobes absent .Lamina simple, symmetric or conspicuously asymmetric, filiform, acicular, subulate, linear, lanceolate, ovate, oblanceolate, obovate or oblong; margins entire, ±flat, involute or incurved; venation parallel, with the midrib rarely conspicuous, and the tertiary venation not reticulate; surfaces not punctate; herbaceous or leathery; distinctive odour absent or foetid. Leaf ligule absent. All the flowers bisexual. Inflorescences terminal, usually consisting of capitula, spikes, panicles or monochasial cymes, or rarely of solitary flowers. Spathes present or absent. Bracts present. Bracteoles present or absent. Pollination by insects or birds. Flowers odourless or fragrant, rarely malodorous; sessile or stalked. Floral disc absent; nectaries absent, or present on the perianth or the carpels. Perianth regular or irregular, of 1 whorl only or all whorls ±similar, with 6 free or fused petaloid segments, imbricate in bud; perianth wheel-shaped, bell-shaped, funnel-shaped or salver-shaped, white, cream, yellow, orange, red, pink, magenta, purple, violet, blue, grey, brown or black, without contrasting markings, or streaked, spotted, etc, membranous; claws present or absent; lobes ±entire. Fertile stamens (2–) 3, opposite to and free of or at least partly fused to the perianth segments, free of the ovary and style, distinct from each other or fused by their filaments into an open or closed tube, all ±equal. Staminodes rarely present. Anthers dorsifixed or basifixed, versatile or not versatile, opening outwards or inwards by longitudinal slits, 2-celled. Ovary inferior or very rarely superior and sessile. Carpels 3, fused; ovary with 3 locules. Style terminal, single and unbranched, or branched above or from the base. Ovules 2–numerous per locule, stalked; placentation axile. Fruit a dry, dehiscent loculicidal capsule; the perianth on the maturing fruit rotting or liquefying. Disseminule macro-surface featureless or winged; micro-surface ±smooth, granulate or rugose, orange, brown or black and glossy or dull. Seeds 6–numerous per fruit. Aril present or absent. Cotyledons 1. Embryo straight.
(Note: this description has been generated from the coded data compiled for the key. Any errors in the key data will be reflected in the descriptions.)

A treatment of the family Iridaceae has been published in:
Flora of Australia 46: 1-66.

Australian genera of Iridaceae (as recognised for the Flora of Australia)

* = all species introduced

*Alophia
*Anomatheca
*Aristea
*Babiana
*Chasmanthe
*Crocosmia
*Dierama
Dietes
Diplarrhena
*Ferraria
*Freesia
*Galaxia
*Gladiolus
Gynandriris
*Herbertia
*Hesperantha
*Hexaglottis
*Homeria
*Homoglossum
*Iris
Isophysis
*Ixia
Libertia
*Moraea
Orthrosanthus
Patersonia
*Romulea
*Schizostylis
*Sisyrinchium
*Sparaxis
*Synnotia
*Tritonia
*Watsonia


Crocosmia crocosmiiflora (flowers)
Photo: M.Fagg © ANBG 


Dierama pulcherrimum (flowers)
Photo: D.Jones © D.Jones 


Dietes robinsoniana (flowers)
Photo: M.Fagg © ANBG 


Ferraria undulata (flowers)
Photo: D.Jones © D.Jones