Sisyrinchium L.
Tufted or shortly rhizomatous, grass-like, annual or perennial. Stems usually compressed, ± winged. Leaves linear, distichous, equitant, basal and cauline. Inflorescence of several subumbellate clusters of 2-many pedicellate flowers emerging successively from a usually 2-valved spathe. Flowers small, cream, blue or violet, rarely white, delicate and fugacious, closing at night, usually cup-shaped below, spreading above; lobes free almost to base, ± equal, often apiculate, outer wider than inner. Stamens inserted at base of perianth, filaments usually united in a cylindrical tube. Style-branches entire. Capsules globose, exserted from spathe-values on elongate filiform pedicels. Seeds numerous, globose, black, ± pitted. Spp. c. 100, mostly of N. and S. America, 1 from Hawaii, 1 from Ireland. Adventive spp. 4.
Key
The taxonomy of the difficult genus Sisyrinchium has not been fully resolved, but recent papers on smaller complexes within it help to clarify the problems. Plants of Sisyrinchium which occur as weeds in N.Z. are easily divided into three kinds by their size and colour (a) S. iridifolium Kunth, the largest, with cream flowers tinged purple, (b) a smaller blue-flowered plant, (c) the smallest, usually annual, with yellow flowers. All three belong to the S. American group possessing " . . . an urceolate perianth . . . short, partially-free filaments, and abruptly tapering "crab-claw" spathe-valves, in contrast to the rotate perianth, wholly fused filaments, and long-tapering spathe-valves of the typical North American Sisyrinchium", see Ward, Phytologia 33,1976, 297. Dr P. Ravenna of Santiago (pers. comm.) has examined blue- and yellow-flowered sisyrinchia from N.Z. and considers that they belong to undescribed subspp. of S. iridifolium. As it is not possible to give a name to these two entities they are treated here as Sisyrinchium blue and Sisyrinchium yellow.
S. californicum (Ker-Gawl.) Dryander with yellow flowers about 3 diam., very unequal spathe-valves and capsules ± 2 cm long, has been once collected in Riccarton, Christchurch, from a roadside gutter - A. J. Healy 72/1, 2.1.1972 (CHR 225145).
