Description:

• Deciduous perennials
• Rootstock a globose corm rooting from below, basal in origin, tunics of fine to moderately coarse fibres
• Stem aerial, rarely subterranean, usually slender and wiry, terete, usually branched, branching often divaricate
• Leaves several, lower 2 or 3 cataphylls; foliage leaves unifacial, with a definite midrib, blades usually plane, rarely H-shaped in transverse section with winged margins, sword-shaped, falcate or linear, sometimes margins thickened, occasionally crisped
• Inflorescence a spike, flowers spirally arranged, occasionally distichous, often flexuose; bracts membranous, occasionally scarious, short, outer usually 3-cuspidate, inner smaller than outer and bicuspidate
• Flowers usually actinomorphic, rarely somewhat zygomorphic, variously coloured, pink, mauve or yellow, sometimes darker in centre, sometimes fragrant, sometimes with nectar from septal nectaries; perianth tube funnel-shaped or filiform throughout, short or elongate
• Tepals subequal, usually spreading
• Stamens symmetrically disposed, arising in throat or at top of tube; filaments included or well exserted, sometimes partly or entirely united; anthers diverging or contiguous, sometimes incompletely dehiscent, occasionally with a bend near base; pollen monosulcate, operculate, exine perforate
• Style included or exserted, dividing at or well above mouth of tube, branches slender, channelled and slightly broadened above or involute and stigmatic apically
• Capsules globose, cartilaginous
• Seeds globose or lightly angled, smooth or ruminate, hard, shiny, surface more or less laevigate, raphal vascular trace excluded
• x = 10 (polyploidy)

Classification Notes:

• Evidently specialised in Ixieae in its dry bracts and actinomorphic flowers, Ixia was considered by Lewis (1962) to be closely related to Dierama
• Subgenus Dichone is distinctive in its unusual, short filaments, small inflated anthers and conduplicate style branches

Nomenclature:

• Ixia L.
  • Linnaeus: 23 (1762)
  • Lewis: 58 (1962)
  • De Vos: 3 (1999)
• Houttuynia Houtt.
  • Houttuyn: 448 (1780) name rejected, not of Thunberg
• Dichone Salisb.
  • Slisbury : 320 (1812)
• Morphixia Ker Gawl.
  • Ker Gawler: 105 (1827)

Distribution & Notes:

• Southern Africa: Species ± 50, mainly in the winter-rainfall region, extending from Namaqualand (Western Cape) and the western Karoo through the southwestern Cape region into the Eastern Cape; most diverse in the SW Western Cape
  • Ixia has a strongly Western Cape distribution with few species extending to the extremes of its range in the north or east

Additional Notes:

• Evidently specialised in Ixieae in its dry bracts and actinomorphic flowers, Ixia was considered by Lewis (1962) to be closely related to Dierama
• Subgenus Dichone is distinctive in its unusual, short filaments, small inflated anthers and conduplicate style branches
• Less specialised species of the genus are pollinated by bees but in section Ixia, the flowers of which have a narrow, closed perianth tube and dark central markings, most species are pollinated by monkey beetles (Scarabaeidae)
• Ixia paniculata is pollinated by the long-proboscid flies, Moegistorhynchus longirostris (Nemestrinidae) and Philoliche rostrata (Tabanidae)
• Other long-tubed species, including I. bellendenii and I. pauciflora, are pollinated by Philoliche rostrata
• Buzz-pollination appears to be characteristic of several species of subgenus Dichone