Psilurus* Fund. Agrostogr. 93 (1820).
Derivation:. From the Greek psilos (slender) and oura (tail) referring to the slender spike.
Key references (keys and floras):. J.P.Jessop, Flora of South Australia 4:1926 (1986); B.K.Simon, Key to Australian Grasses 153 (1993); S.W.L.Jacobs and K.L.McClay, Flora of New South Wales 4: 616 (1993); N.G.Walsh, Flora of Victoria 2: 409 (1994); D.Sharp and B.K.Simon, AusGrass (2002); J.P.Jessop, Grasses of South Australia 160–162 (2006); S.W.L.Jacobs, R.D.B.Whalley & D.J.B.Wheeler, Grasses of New South Wales, 4th ed, 358–359 (2008); A.Wilson (ed.), Flora of Australia 44A: Poaceae 2: 347–348 (2009)
W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (116).
Naturalised. 1 species, from Mediterranean to Afghanistan. SA, NSW, and Vic.
Habit. Slender annual, tufted (or single culms). Leaf blades narrow. Ligule an unfringed membrane.
Inflorescence. Inflorescence a single spike (thin, wiry, ultimately disarticulating, the spikelet initially sunken, ultimately spreading). Spikelet-bearing axes disarticulating at joints.
Spikelets. Spikelets all partially embedded in rachis (widely spaced), laterally compressed, solitary, sessile (broadside to axis); with naked rachilla extension. Fertile spikelets adaxial (with lower glume against rachis) (the single (upper) glume on the outside), laterally compressed, disarticulating above glumes (the terminal spikelet) or falling with glumes (the lower spikelets), with distinctly elongated rachilla internodes between florets.
Glumes. Glumes one per spikelet (except for the terminal spikelet, with two), (the upper, only glume) shorter than adjacent lemmas (very small), pointed, awnless, non-keeled. Upper glume 1 nerved (there being no lower glume).
Florets. Fertile florets 1(–2). Lemmas linear-lanceolate, membranous to leathery, entire at apex or incised, awned, 3 nerved, 1 keeled. Awns 1, from a sinus or apical, non-geniculate, straight, hairless (scabrous), much shorter than body of lemma to much longer than body of lemma (2.3–5.5 mm long). Awn bases flattened. Palea relatively long (as long as the lemma), tightly clasped by lemma, entire, thinner than lemma (membranous), 2 nerved, 2 keeled. Palea keels wingless. Distal incomplete florets underdeveloped (rudimentary). Callus short, blunt (glabrous). Lodicules 2. Stamens 1. Stigmas 2. Grain small (about 4 mm long), longitudinally grooved to not grooved, compressed laterally, scabrous. Hilum long-linear. Embryo small. Endosperm hard.
Kranz Anatomy. C3.
2n = 14 and 28, 2 and 4 ploid, commonly adventive.
Habitat. Dry places. Species of open habitats.
Classification. Pooideae; Poeae.
Notes. An isolated genus, apparently related to Vulpia (Clayton and Renvoize, 1986).
Types Species. P. nardoides Trin. nom.illeg..
Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: Naturalised.