Poa pusilla

Features

Slender, often delicate, open, perennial tufts, 5-c. 35 cm, with few, very narrow, flaccid, bright green leaves, and slender, long-creeping rhizome; branching extravaginal; leaf-blades persistent. Leaf-sheath greenish purple becoming light brown, ± membranous, distinctly keeled, ribs strong, whitish, shaggy pubescent-scabrid, or minutely scabrid throughout or only near hyaline margins, occasionally with a few longer hairs on margins near ligule, rarely completely glabrous. Ligule 0.2-0.5 mm, truncate, ciliate, sometimes erose, abaxially with minute hairs. Leaf-blade (1)-5-15-(25) cm ×c. 0.5 mm diam., folded, rarely flat and wider, margins inrolled, abaxially distinctly ribbed, glabrous, adaxially with scattered short hairs especially on midrib, tip subacute to curved, scabrid on midrib. Culm 3-30-(50) cm, very slender, erect or drooping above, internodes glabrous. Panicle 1.5-8.5 cm; branches spreading, few, filiform, scabrid, bearing 1-4 spikelets at tips. Spikelets 3-7.5 mm, 2-5-(7)-flowered, yellow-green, faintly purplish. Glumes subequal, 2-4-(4.5) mm, 3-nerved, narrow elliptic- to ovate-lanceolate, acute or subacute, smooth, midnerve and sometimes lateral nerves sparsely scabrid. Lemma 2-4-(5) mm, 5-nerved, oblong- to ovate-elliptic, obtuse, midnerve with long silky crinkled hairs in lower ½, sometimes scabrid above hairs, lateral nerves usually with conspicuous silky hairs near base or in lower ½, internerves usually smooth, rarely finely scabrid, with hyaline band at slightly erose tip. Palea 2-3.5 mm, keels short ciliate-scabrid, interkeel short pubescent-scabrid, flanks smooth to scabrid. Callus with thick tuft of long, silky crinkled hairs. Rachilla (0.3)-0.6-0.8 mm, with scattered long hairs. Lodicules c. 0.5 mm. Anthers 1-2 mm. Caryopsis c. 1 × 0.5 mm. 2n= 28.