Paractaenum Essai Agrost. 47 (1812).
Derivation:. From Greek para (like) and ktenion (little comb), alluding to the bristly spikelets.
Key references (keys and floras):. G.Bentham, Flora Australiensis 7: 459–462 (1878) as Plagiosetum; C.A.Gardner, Flora of Western Australia 1 Gramineae 245–246 (1952) and 290 as Plagiosetum; J.W.Vickery, Flora of New South Wales, Gramineae 19: 223–224 (1975) and 224–225 as Plagiosetum; M.Lazarides, Flora of Central Australia 482 (1981) and 200 as Plagiosetum; J.C.Tothill and J.B.Hacker, Grasses of Southern Queensland 324–325 (1983)and 348–349 as Plagiosetum; J.P.Jessop, Flora of South Australia 4: 1970 (1986) and 1974–1975 as Plagiosetum; R.D.Webster, Australian Paniceae 146–149 (1987); B.K.Simon, Key to Australian Grasses 138 (1993); S.W.L.Jacobs and K.L.McClay, Flora of New South Wales 4: 493 (1993) and 494 as Plagiosetum; D.Sharp and B.K.Simon, AusGrass (2002); J.P.Jessop, Grasses of South Australia 465–467 (2006); S.W.L.Jacobs, R.D.B.Whalley & D.J.B.Wheeler, Grasses of New South Wales, 4th ed, 319 and 342–343 as Plagiosetum (2008).
W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (510).
Native, endemic. 2 species, from mainland Australia. WA, NT, SA, Qld, and NSW.
Habit. Annual, tufted. Leaf blades narrow. Ligule a fringed membrane.
Inflorescence. Inflorescence of spicate main branches (with up to 5 spikelets per raceme, but reducing to one or two), a spike-like panicle or a racemose panicle with spikelets all similar, the racemes finally deflexing, non-digitate. Spikelet-bearing axes much reduced or spikelike, falling entire (the short branches articulated at their bases, falling whole).
Spikelets. Spikelets all partially embedded in rachis to not all embedded, dorsally compressed, 2 flowered, with 1 fertile floret, with raceme axis extending into a bristle, subtended by solitary bristles, solitary or several in a whorl, shortly pedicelled. Fertile spikelets with lower incomplete floret(s), oblong or elliptic or lanceolate or ovate or obovate, abaxial (with lower glume on side away from rachis), falling with glumes (and with the branch).
Glumes. Glumes relatively large, unequal, (the upper glume, which equals the spikelet) long relative to adjacent lemmas, awnless, non-keeled. Lower glume 3–5 nerved. Upper glume 9–13 nerved.
Florets. Lower incomplete floret(s) sterile. Lemmas awnless, 9–11 nerved, exceeding fertile lemmas, less firm than fertile lemmas (herbaceous-membranous, similar to the upper glume), not becoming indurated. Fertile florets 1. Lemmas decidedly firmer than glumes (leathery or cartilaginous), rugose, becoming indurated (slightly), yellow in fruit or brown in fruit, entire at apex, pointed or blunt, muticous, 3–5 nerved, glabrous (shortly ciliolate at the apex), having flat margins not tucked into palea. Palea relatively long (elliptical), entire, textured like lemma, slightly indurated (like the lemma). Lodicules 2. Stamens 3. Grain small, compressed dorsiventrally. Hilum short. Embryo small.
Kranz Anatomy. C4.
Habitat. Sandy places, sometimes maritime. Species of open habitats.
Classification. Panicoideae; Paniceae.
Notes. A derivative of Paspalidium with deciduous racemes (Clayton & Renvoize, 1986).
Types Species. P. novae-hollandiae P.Beauv.
Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: Endemic.