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The southern African winter-rainfall genus Ixia L., with almost 100 species, is divided into four sections, with sect. Ixia distinguished by a filiform perianth tube closely clasping the style, and filaments that occlude the mouth of perianth tube and are sometimes partly united but never decurrent in the tube. The section was last revised by G. J. Lewis in 1962, at which time it included 18 species and several varieties. Five species have since been described, I. atrandra Goldblatt & J.C. Manning, I. calendulacea Goldblatt & J.C. Manning, I. frederickii M.P. de Vos (subsequently reduced to synonymy in I. dubia Vent.), I. mostertii M.P. de Vos and I. superba Goldblatt & J.C. Manning. One more, I. purpureorosea G.J. Lewis, was later transferred to sect. Hyalis (Baker) Diels. Here we provide a revised key and synopsis of sect. Ixia as the final contribution in our series of systematic studies in the genus, which already includes revisions of sects. Dichone (Salisb. ex Baker) Goldblatt & J.C. Manning, Hyalis (Baker) Diels and Morphixia (Ker Gawl.) Pax. We recognize a total of 29 species in sect. Ixia , including five new species: I. alticola Goldblatt & J.C. Manning and I. angelae Goldblatt & J.C. Manning from the central Cedarberg; late-flowering I. helmei Goldblatt & J.C. Manning from near Bot River; I. roseoalba Goldblatt & J.C. Manning from the western Langeberg; and yellow- or pink-flowered, usually stoloniferous I. sarmentosa Goldblatt & J.C. Manning from marshes and seeps at low elevations in Western Cape. We also recognize white-flowered I. leucantha Jacq. (currently a synonym of I. polystachya L.), I. fuscocitrina Desf. ex DC. (currently a variety of I. maculata L.), and elevate I. polystachya var. longistylis M.P. de Vos to species rank as I. longistylis (M.P. de Vos) Goldblatt & J.C. Manning. I. patens var. linearifolia G.J. Lewis and I. viridiflora var. minor M.P. de Vos are reduced to synonymy in their respective species.

A revised classification is presented for Ixia L., a southern African genus restricted to the winter rainfall zone of the western part of the subcontinent, in which the four sections Dichone (Salisb. ex Baker) Goldblatt & J.C.Manning, Hyalis (Baker) Diels, Ixia, and Morphixia (Ker Gawl.) Pax are recognized and diagnosed. The circumscription of sect. Hyalis is emended to include both short- and long-tubed species, mostly with four or more leaves with the uppermost not sharply differentiated from the lower. This contrast with sect. Morphixia , also with short- and long-tubed species, in which the entirely sheathing uppermost leaf (rarely upper two leaves) is distinct from the lower two or rarely three leaves, which have well-developed blades. We revise these two sections, recognizing 18 species in sect. Hyalis , including the two new species, I. linderi and I. recondita , and recognizing 31 species in sect. Morphixia , including the 11 new species, I. alata , I. cedarmontana , I. dolichosiphon , I. ecklonii , I. linearifolia , I. monticola (previously included in I. latifolia var. angustifolia ), I. pavonia , I. parva and I. ramulosa (raised from varietal rank as var. parviflora and var. ramulosa respectively of I. latifolia ), I. saundersiana and I. stenophylla (previously I. fucata var. filifolia ). We also provide a new name, I. mollis for the illegitimate homonym I. flaccida . Lastly, we transfer I. purpureorosea from sect. Ixia to sect. Hyalis . We recognize eight informal series, three in sect. Hyalis and five in sect. Morphixia . With these changes and additions the genus Ixia now comprises 78 species.