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Pakistan | Family List | Poaceae

Piptatherum P. Beauv., Ess. Agrost. 17. 1812. Boiss., Fl. Or. 5:506. 1884; Freitag in Notes R. Bot. Gdn Edinb. 33:341-408. 1975; Tzvelev, Poaceae URSS 596. 1976; Tutin in Tutin et al., Fl. Eur. 5:246. 1980.

  • Oryzopsis auct. non Michx.
  • Urachne Trip.

    Perennials. Glumes ± equal, as long as the spikelet; lemma usually shorter than the glumes, rarely equalling them, covering only the margins of the palea, ovate or lanceolate to obovate or elliptic, dorsally compressed, hairy or glabrous, entire or minutely bibbed at the tip; callus short and obtuse; awn usually deciduous, straight and erect, never twisted.

    A genus of about 25 species in the Old World subtropics; 7 species occur in Pakistan.

    Piptatherum angustifolium (Regel) Boiss., Piptatherum barbellatum Mez, Piptatherum caerulescens (Desf.) P. Beauv. and Piptatherum molinioides Boiss. have all been reported as occuring in Pakistan, but on the basis of incorrectly identified material.

    Piptatherum is a difficult genus to name, partly because the species are all so variable and partly because the only useful distinguishing features tend to be cryptic in nature. It is virtually impossible to write a key for use in the field since identification of specimens relies on characters that are inaccessible except when magnifications of up to 20x are available. Identification is best attempted at or just after anthesis as both anthers and the fragile awn are of critical importance. Only one species has glabrous lemmas (Piptatherum vicarium) and one glabrous anther tips (Piptatherum hilariae), otherwise the species are all very much alike, differing only in length and position of awn, lemma shape (best seen in mature specimens) and density and distribution of lemma pubescence.

    1 Lemma completely glabrous except sometimes for two tufts of hair at the base   Piptatherum vicarium
    + Lemma variously hairy on the body   (2)
    2 (1) Awn terminal (or if minutely subterminal then more than 6 mm long); lemma entire at tip; anther tips always bearded   (3)
    + Awn clearly subterminal with a sharp bend at the base; lemma minutely but distinctly bilobed at the tip; anther tips bearded or not   (6)
    3 (2) Awn usually exceeding 6 mm   (4)
    + Awn rarely exceeding 4 mm   (5)
    4 (3) Lemma at least (4.5-)5 mm long; awn without a constriction, continuous with the lemma tip and subpersistent   Piptatherum aequiglume
    + Lemma 3-4(-5) mm long; awn with a distinct constriction at the very base across which it readily disarticulates   Piptatherum munroi
    5 (3) Lemma ovate, 3.2-4.5 mm long, 1.3-1.5 mm wide, partially hairy, glabrous at the tip and along the dorsal line, the lower half usually glabrescent   Piptatherum baluchistanicum
    + Lemma narrowly lanceolate to almost linear, 4-6.5 mm long, rarely shorter, 0.8-1.3(-1.5)mm wide, hairy all over with stiff hairs   Piptatherum laterale
    6 (2) Anther tips distinctly bearded; lemma with hairs c.0.5 mm long, these extending to the tip and ± concealing the lobes; lemma body narrowly lanceolate to almost linear   Piptatherum gracile
    + Anther tips glabrous or with a few hairs, but never distinctly bearded; lemma with hairs 0.2-0.3 mm long, these not extending to the tip; lemma body ovate to elliptic, often slightly beaked at the tip   Piptatherum hilariae

    Lower Taxa

    Related Synonym(s):


    Related Objects  

    Flora of China  
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