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FOC | Family List | FOC Vol. 22 | Poaceae

51. Ptilagrostis Grisebach in Ledebour, Fl. Ross. 4: 447. 1852.

细柄茅属 xi bing mao shu

Stipa sect. Ptilagrostis (Grisebach) Hackel.

Perennials, densely tufted. Culms slender, erect. Leaf blades setaceous. Inflorescence an open or loosely contracted panicle. Spikelets with 1 floret, bisexual, disarticulating above glumes; rachilla extension absent; glumes lanceolate to elliptic-oblong, subequal, a little longer than floret, herbaceous to scarious, 1–3-veined, apex obtuse to acuminate; callus short, obtuse, shortly bearded; lemma lanceolate, terete, papery, 3–5-veined, pubescent or pilose, margins not overlapping, apex minutely or distinctly 2-toothed, awned from between teeth; awn persistent, plumose throughout, 1(or 2)-geniculate, column twisted; palea midline exposed between lemma margins. Lodicules 3. Stamens 3, anthers glabrous or apex with hair tufts. Stigmas 2.

Eleven species: E Tajikistan (Pamirs) to Russia (NE Siberia), also W United States, on mountains; seven species (two endemic) in China.

Ptilagrostis pelliotii is a distinct and readily separable species, but most of the remainder of the genus comprises a complex of intergrading forms and local variants. The genus is weakly separated from Stipa, S. subsessiliflora being intermediate.

1 Ligule truncate, ciliate; leaf blades fairly stiff; glumes lanceolate, sharply acuminate; gravelly and rocky places on desert plains   1 P. pelliotii
+ Ligule oblong or lanceolate, rounded, glabrous; leaf blades softer; glumes elliptic or oblong-lanceolate, obtuse to acute; alpine meadows and high hilly steppe   (2)
2 (1) Panicle open, 3–5 cm wide; branches up to 6 cm, spreading   (3)
+ Panicle contracted, 0.7–2 cm wide; branches 0.3–2.8 cm, suberect or narrowly ascending   (5)
3 (2) Glumes 2.6–3.5 mm; awn 0.6–1 cm.   2 P. luquensis
+ Glumes 4.5–7 mm; awn 1–3 cm   (4)
4 (3) Anthers 1–2 mm, with hair-tufts at apex; glumes gray-brown or purplish, whitish at apex; awn 1–2 cm.   3 P. dichotoma
+ Anthers 1.8–3 mm, glabrous; glumes dark-purple at base, otherwise whitish; awn 1.5–3 cm.   4 P. mongholica
5 (2) Spikelets 8–12 mm; glumes unequal.   5 P. yadongensis
+ Spikelets 4–7 mm; glumes subequal   (6)
6 (5) Panicle with sheathing membranous bract at base of lowest branches; spikelets purple; lemma 3.5–5 mm; awn 1–1.5 cm.   6 P. concinna
+ Panicle without membranous bract at base of lowest branches; spikelets brownish mauve; lemma 4.5–6 mm; awn 1.5–2 cm   7 P. junatovii

Lower Taxa


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