Lachnagrostis billardierei subsp. billardierei

Detailed description

Stiffly tufted, glaucous to bluish-green perennial grass, 100–600 mm tall, with capillary-branched panicles sometimes overtopped by leaves. Branching intravaginal. Leaf-sheath papery, with wide membranous margins, closely striate, smooth but sometimes scaberulous above on nerves, light brown to amber. Ligule 1.0–4.5 mm, tapered above, entire to erose, undersides scabrid. Leaf-blade 50–240 × 2.5–10.0 mm, flat, harsh, scaberulous on ribs and on margins throughout, more or less abruptly narrowed to firm, more or less blunt, more or less cucullate apex. Culm 40–400 mm, erect, or decumbent at base, included within uppermost leaf-sheath, internodes densely finely scabrid. Panicle 60–240 × 100–240 mm, purple-green to wine-red, lax, with long, whorled, ascending branches, later spreading and panicle becoming as broad as long; rachis and branches scaberulous, spikelets single at tips of ultimate panicle branchlets, on pedicels thickened above. Spikelets 4–6 mm, pale green, purple-green or red-green. Glumes 1–3-nerved, narrow-lanceolate, acuminate, usually smooth, sometimes sparsely scabrid, margins wide, hyaline, mid-nerve scabrid. Lemma 3–4 mm, ± ⅔ length of glumes, smooth, or often scabrid above (especially on nerves), membranous, shining, elliptic-lanceolate, lateral nerves excurrent to short awns 0.5–1.0 mm long; central awn 4.5–9.0 mm, fine, geniculate from lower third of lemma (rarely middorsal). Callus hairs more or less dense, very short, 0.3–0.7 mm, c. one-tenth length of lemma. Rachilla prolongation 0.5–1.0 mm, tipped by a thick tuft of hairs 1.0–1.5 mm and more or less equivalent in length to palea. Lodicules slightly > 0.5 mm, lanceolate, acute. Anthers 0.5–1.0 mm. Seed 1.3–1.8 × 0.5–0.8 mm.