Flora of New Zealand Series

smooth summer grass

Summer annuals, forming loose or compact dark purple-green tufts. Leaf-sheath submembranous, striate, glabrous or rarely with a few hairs on margins, light green, folded. Ligule 1-1.5-(2) mm, membranous, glabrous, ± truncate, erose. Leaf-blade 3-6 cm × 3-5 mm, lanceolate, ± rounded at base, glabrous; margins minutely scabrid throughout with a few long hairs near ligule. Culm 7-20-(30) cm, slender, geniculate-ascending, spreading or prostrate, internodes glabrous. Racemes 2-4-(5), 2.5-10 cm, subdigitate, very slender, spreading at maturity; rachis flat, 0.5-1 mm wide, narrowly winged, sparsely long-hairy at base, margins finely scabrid; pedicels ± 3-angled, rarely flattened, sparsely, finely prickle-toothed. Spikelets c. 2 mm, close-set in pairs or triplets, shortly, unequally pedicelled, elliptic or oblong-elliptic, hairs minute, numerous, swollen-tipped. Lower glume 0, or a minute scarious rim, upper c. 2 mm, ≈ spikelet, submembranous, 3-(5)-nerved, internerves with bands of dense short fine hairs. Lower floret: lemma = spikelet, submembranous, 5-nerved, nerves glabrous, outer internerves sparsely to densely fine-hairy; palea minute. Upper floret: lemma = spikelet, dark chestnut-brown, glabrous, acute, margins wide, hyaline, enfolding palea; palea of similar texture to lemma, margins widened below to enfold caryopsis; anthers 0.4-0.7 mm; stigmas purple; caryopsis c. 1.5 × 0.8 mm, oblong.

N.: Auckland (early records, but not seen since 1970), scattered localities southwards from Waikato and Bay of Plenty; S.: Marlborough, Otago (Dunedin, Alexandra, Clyde). Sandy or dry ground, pasture, roadsides, metal drives.

Naturalised from Eurasia.

Webster (1984 op. cit. p. 187) noted that D. ischaemum is often confused with D. violascens especially when both invade habitats which are frequently trampled or cut.