Pentapogon lautumia

Detailed description

Robust grey-green to orange-green tufts 450–650 mm tall. Branching extravaginal. Leaf-sheath chartaceous with membranous margins, more or less distinctly ribbed, glabrous, straw-coloured, or reddish purple, especially in culm leaves. Ligule 0.7–1.0 mm long, truncate, erose, sparsely ciliate, undersides scabrid. Leaf-blade 60–200 × 15–30 mm, greyish green maturing orange-green or reddish, undersides smooth, upper surface strongly ribbed, prickle-toothed on ribs; margins finely prickle-toothed. Culm 300–450 mm long, nodes green to purple with an upper fringe of dense, appressed hairs, internodes glabrous. Panicle 100–160 × 10–15 mm, linear-lanceolae, dense, contracted above, longer lower branches in slightly more distant clusters, scarcely spreading, spikelet bearing to base; rachis, branches and pedicels with short hair-like prickle-teeth. Spikelets 6–8 mm, green to straw-coloured or suffused with purple. Glumes 1-nerved, equal or upper very slightly longer, c. 6 mm, submembranous, elliptic-lanceolate, acuminate, keels finely prickle-toothed. Lemma less than or equal to glumes, 6–7 mm, subcoriaceous, papillose, minutely prickle-toothed above, apex bifid with hyaline finely acuminate lobes 0.5–1.0 mm long; awn 8–12 mm, mid-dorsal, or arising from slightly above midway, geniculate, twisted, very hairy below. Palea less than lemma, folded, keels prickle-toothed above, apex ciliate. Callus c. 0.2 mm long, hairs up to 4 mm long. Rachilla 0.2–0.7 mm, glabrous or with a few hairs; prolongation 0.5 mm long. Lodicules 0.5 mm, cuneate, ciliate. Stamens 3; anthers 1.0–1.5 mm long. Ovary 1.0–1.3 mm; stigma-styles 0.7–1.5 mm long, hairs almost to base. Seed 3.5 × 1.0 mm, beaked.