Flora of New Zealand Series

; Holotype: CHR 467998! B. D. Rance Southland, Omaui, Three Sisters Dune, sand dune, 25.1.1990.

Lax, bluish green, perennial tufts, 15-35 cm, usually with narrow, involute leaves and very lax panicles; branching extravaginal, each shoot with 1-2 blunt-tipped sheaths at base and with the lowest leaf-blade often much reduced. Leaf-sheath submembranous, distinctly ribbed, smooth or sometimes scabrid above. Ligule (1.5)-2.5-4.5 mm, tapered above to acute tip or denticulate, abaxially scabrid. Leaf-blade 6-16 cm × 0.4-0.8 mm diam., inrolled, to 1.2 mm wide if flat, abaxially smooth to scabrid (especially near tip), adaxially finely scabrid; margins finely scabrid, tip fine, obtuse. Culm 10-15 cm, slender, usually included within uppermost leaf-sheath, internodes glabrous. Panicle (7)-10-16 × 1.5-12-(15) cm; branches few, long, filiform, ± closely, finely scabrid, each tipped by a single spikelet. Spikelets (4.5)-5-7 mm, light green. Glumes ± equal, narrowly elliptic-lanceolate, scabrid above and on midnerve and hyaline margins, or sometimes sparsely scabrid throughout. Lemma (2.8)-3.2-3.7 mm, ± ½ length of glumes, 5-nerved, densely covered throughout by long, silky hairs, oblong, truncate, lateral nerves minutely excurrent, rarely lemma less hairy near apex and scabrid nerves clearly visible; awn 4-5.5-(6) mm, very fine, straight or ± curved, ± middorsal. Palea ⅔-¾ length of lemma, keels c. 0.1 mm apart, apex bifid. Callus hairs dense, 1.5-2 mm, to ⅔ length of lemma. Rachilla prolongation 0.5-0.8 mm, tipped by a dense tuft of hairs 1-2 mm. Lodicules 0.9-1.2 mm, linear. Anthers 0.9-1.3 mm. Caryopsis c. 2 × 0.7-1 mm.

S.: southern Westland (Jacksons Bay), Fiordland (Milford Sound), and southern coast between Catlins and Bluff; St. Coastal in damp sand; near sea level.

Endemic.

Lachnagrostis ammobia resembles L. lyallii and L. elata in its lax habit with extravaginal branching. It may be distinguished from L. lyallii, though not from L. elata, by the very lax panicle, long lemma and ± straight awn.