Ichnanthus Essai Agrost. 56 (1812).
Derivation:. From Greek ichnos (trace) and anthos (flower), referring to the small appendages at the base of the florets.
Taxonomic revisions, nomenclatural references:. M.T.Stieber, Syst. Bot. 12: 187–216 (1987).
Key references (keys and floras):. E.E.Henty, Manual Grasses New Guinea 110–111 (1969); M.Lazarides, Tropical Grasses S.E. Asia 122–123 (1980); R.D.Webster, Australian Paniceae 100–101 (1987); B.K.Simon, Key to Australian Grasses 125 (1993); S.W.L.Jacobs and S.M.Hastings, Flora of New South Wales 4: 492–493 (1993); D.Sharp and B.K.Simon, AusGrass (2002).
W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (452).
Native. 33 species, from tropical America, Indomalayan region and Australia. 1 species in Australia, Qld. Also New Guinea and Malesia.
Habit. Annual or perennial, tufted or decumbent. Leaf blades broad or narrow. Ligule short a fringed membrane or a fringe of hairs.
Inflorescence. Inflorescence paniculate or of spicate main branches (the primary branches sometimes unbranched), an open panicle with branches ending in single spikelets, open.
Spikelets. Spikelets laterally compressed to dorsally compressed (the upper lemma dorsally compressed), 2 flowered, with 1 fertile floret, solitary. Fertile spikelets with lower incomplete floret(s), oblong or elliptic or lanceolate or ovate or obovate or oblanceolate, adaxial (with lower glume against rachis) (or not orientated), disarticulating above glumes or falling with glumes, with distinctly elongated rachilla internodes between florets. Upper floret borne on a swollen stipe. Stipe beneath upper floret not filiform, curved, not swollen (about 1 mm long, bearing a small, white, annular, membranous, minutely two-lobed appendage below the palea), homogeneous.
Glumes. Glumes unequal (the lower usually about 1/2 to 3/4 of the spikelet length), (the longer) long relative to adjacent lemmas, pointed, awnless, similar (membranous- herbaceous). Lower glume 3–7 nerved. Upper glume 5–9 nerved.
Florets. Lower incomplete floret(s) male. Lemmas awnless, 7 nerved, exceeding fertile lemmas, less firm than fertile lemmas, not becoming indurated. Fertile florets 1. Lemmas decidedly firmer than glumes (papery to leathery), smooth, becoming indurated, white in fruit or yellow in fruit, muticous, with a clear germination flap, 5–7 nerved, glabrous (shiny), having margins tucked into palea. Palea relatively long, entire, textured like lemma, indurated, 2 nerved. Lodicules 2. Stamens 3. Disseminule often deciduous before the rest of the spikelet, comprising the fruit and the upper palea on the stipe-like rachilla joint, enclosed by the lower lemma. Grain small, compressed dorsiventrally. Hilum short. Embryo large.
Kranz Anatomy. C3.
2n = 18, 20, 40, and 54.
Habitat. Mesophytic. Forest, grassland and disturbed ground. Shade species and species of open habitats.
Classification. Panicoideae; Paniceae.
Notes. A genus of varying habit from tall canes to forest-like herbs and rambling weeds, which includes several polymorphic complexes of great taxonomic difficulty. It has appendages at the base of the florets, and their function is unknown (Clayton and Renvoize, 1986).
Types Species. I. panicoides P.Beauv.
Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: IM -Trop. Am.