Iseilema Nova Acta Regiae Soc.Sci. Upsal. ser.3, 2: 250 (1856).
Derivation:. From Greek isos (equal) and eilema (a covering or involucre), alluding to the four involucral spikelets.
Taxonomic revisions, nomenclatural references:. C.E.Hubbard, Hookers Icones Plantarum 33:t. 3286: 1–16 (1935); S.T.Blake, Proc. Royal Soc. Qld 48: 82–94 (1938).
Key references (keys and floras):. G.Bentham, Flora Australiensis 7: 541–544 (1878) as Anthistiria; C.A.Gardner, Flora of Western Australia 1 Gramineae 345–353 (1952); J.W.Vickery, Flora of New South Wales, Gramineae 19: 63–66 (1961); M.Lazarides, Tropical Grasses S.E. Asia 53–54 (1980); M.Lazarides, Flora of Central Australia 492–493 (1981); J.C.Tothill and J.B.Hacker, Grasses of Southern Queensland 286–288 (1983); J.P.Jessop, Flora of South Australia 4: 1990–1992 (1986); B.K.Simon, Flora of the Kimberley Region 1181–1185 (1992); B.K.Simon, Key to Australian Grasses 127 (1993); S.W.L.Jacobs and C.A.Wall, Flora of New South Wales 4: 448–449 (1993); D.Sharp and B.K.Simon, AusGrass (2002); J.P.Jessop, Grasses of South Australia 525–528 (2006); S.W.L.Jacobs, R.D.B.Whalley & D.J.B.Wheeler, Grasses of New South Wales, 4th ed, 286–287 (2008).
W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (623).
Native. 20 species, from the Indomalayan region and Australia. 12 species in Australia, WA, NT, SA, Qld, and NSW. Also Malesia.
Habit. Annual or perennial (usually delicate, often with coloured leaves, culms and spathes), tufted. Leaf blades narrow. Ligule a fringed membrane.
Inflorescence. Inflorescence falsely paniculate (the single racemes or tight clusters gathered with their spatheoles into a narrow false panicle), a spatheathe panicle, open, spatheate, terminal branches contracted into tight heads, a compound pseudo-inflorescence. Spikelet-bearing axes much reduced (with small, short spike-like racemes, similar to Themeda but disarticulating below the involucral spikelets), with heteromorphic spikelets, falling entire (complete with the involucral spikelets, and sometimes with the investing spatheole, which may then be indurated).
Spikelets. Spikelets dorsally compressed, 2 flowered, with 1 fertile floret, associated with bractiform involucres (comprising the involucral spikelets), distal to the involucral whorl in triplets, sessile and pedicelled (two pedicellate members per heterogamous triplet, the pedicels filiform), in pedicelled/sessile combinations; sessile spikelet with lower incomplete floret. Fertile spikelets falling with glumes (and with the whole racemelet, the upper pedicellate pair usually smaller than the sessile,sometimes much reduced, deciduous or not).
Glumes. Glumes more or less equal, long relative to adjacent lemmas, awnless. Lower glume flattened on back, relatively smooth, 8–10 nerved. Upper glume 3 nerved.
Florets. Lower incomplete floret(s) sterile. Lemmas awnless, 0 nerved or 3 nerved, exceeded by fertile lemmas, not becoming indurated (hyaline). Fertile florets 1. Lemmas stipitate beneath the awn, less firm than glumes, not becoming indurated, entire at apex or incised, awned, without a germination flap, 1 nerved, glabrous. Awns 1, from a sinus or apical, geniculate. Palea absent. Lodicules 2. Stamens 1–3. Grain small, compressed dorsiventrally. Hilum short. Embryo large. Pedicelled spikelets present, similar in shape to sessile spikelet, sterile or male.
Kranz Anatomy. C4.
2n = 6, 8, 18, 28, and 36, 2, 7, and 9 ploid (?).
Habitat. Grassland. Species of open habitats.
Classification. Panicoideae; Andropogoneae.
Notes. Modification of the raceme is extreme, the sessile and homogamous spikelets being fused at their base into a single unit which falls as a whole. There is an obvious similarity to Themeda, but no sign of the latter's characteristic pedicelled spikelet callus (Clayton and Renvoize, 1986).
Types Species. I.prostratum (L.) Anderss.
Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: Indo-Malayan.