Piptochaetium* Rel. Haenk. 1: 222 (1830).
Derivation:. From the Greek pipto (to fall) and chaite (bristle), alluding to deciduous awns.
Key references (keys and floras):. B.K.Simon, Key to Australian Grasses 145 (1993); N.G.Walsh, Flora of Victoria 2: 399–400 (1994); D.Sharp and B.K.Simon, AusGrass (2002); A.Wilson (ed.), Flora of Australia 44A: Poaceae 2: 68–70 (2009).
W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (100).
Naturalised. About 30 species, from North & (mainly) South America. 1 species in Australia, Vic.
Habit. Perennial, tufted. Leaf blades broad or narrow (narrow, usually involute). Ligule an unfringed membrane.
Inflorescence. Inflorescence paniculate.
Spikelets. Spikelets laterally compressed to subterete, usually long pedicelled; with rachilla terminating in a floret. Fertile spikelets laterally compressed to subterete, disarticulating above glumes.
Glumes. Glumes more or less equal, about equal to spikelet or exceeding florets, long relative to adjacent lemmas (usually exceeding the floret), hairless, pointed (abruptly acuminate), awnless, non-keeled (convex on the back), similar (thin). Upper glume 3–7 nerved.
Florets. Fertile florets 1. Lemmas often dark-pigmented, sometimes cylindrical, usually asymmetrically obovoid to subglobose or lenticular
, involute (the margins involute, fitting into the paleal groove), saccate (usually) or not saccate, decidedly firmer than glumes, becoming indurated (smooth, verrucose, striate or tuberculate, the epidermis without silica bodies), awned, without a germination flap, 5 nerved, having margins tucked into palea, 1 keeled (usually somewhat compressed and keeled). Awns 1, apical (the summit of the lemma often expanded into a corona), non-geniculate or geniculate (often bi-geniculate), hairless (glabrous) or hairy, much longer than body of lemma or much shorter than body of lemma (much reduced, in P. cucullatum), deciduous or persistent. Palea relatively long (the apex of the keel projecting as a minute point above the summit of the lemma), entire, 2 nerved (these fairly adjacent), 2 keeled. Callus short. Lodicules 2, or 3. Stamens 3. Stigmas 2. Grain longitudinally grooved. Hilum long-linear. Endosperm hard.
Kranz Anatomy. C3.
2n = 22 and 44, 2 and 4 ploid, commonly adventive.
Habitat. Mesophytic to xerophytic. Species of open habitats.
Classification. Pooideae; Stipeae.
Notes. The genus can imitate Stipa and Nassella, but is readily distinguished by its grooved palea (Clayton and Renvoize, 1986).
Types Species. P. setifolium J.S.Presl.
Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: Naturalised.