Flora of New Zealand Series

summer grass

Summer annuals, forming loose, dull green to purplish tufts, ± creeping and rooting at lower nodes. Leaf-sheath submembranous, striate, light green, with few to numerous tubercle-based hairs. Ligule 0.5-1 mm, membranous, glabrous, truncate, erose. Leaf-blade (1.5)-3-6.5 cm × 3-9 mm, soft, narrow-lanceolate, rounded at base, flat, glabrous, or with long fine hairs; margins minutely scabrid, rather abruptly narrowed to acute tip. Culm (15)-20-30-(115) cm, ascending to erect from prostrate base, nodes loosely hairy, internodes glabrous. Racemes (2)-3-6-(8), (3.5)-5-15-(20) cm, slender, digitate or subdigitate, finally spreading; rachis 3-angled, winged, 0.7-1 mm wide, scabrid on angles; pedicels 3-angled, angles scarcely scabrid. Spikelets 2.5-3 mm, in pairs, ovate to oblong-elliptic, subacute, green to purplish, close-set, unequally short-pedicelled. Lower glume 0.2-0.5 mm, a minute ± triangular rim, rarely with a few hairs, upper 1-1.5 mm, to ½ length of spikelet, lanceolate, acute, 3-nerved, membranous, with fine hairs near margins. Lower floret: lemma = spikelet, 7-nerved, nerves minutely scabrid, a band of fine hairs just inside margin; palea minute. Upper floret: lemma = spikelet, grey-brown, firm, glabrous, acute, margins hyaline, enfolding palea; palea similar to lemma in texture but slightly smaller; anthers 0.7-1 mm; stigmas purple or brown; caryopsis 1.5-2 mm, oblong.

N.: common throughout; S.: scattered in Nelson, Marlborough, and Westland, more common in Canterbury, in Central Otago and at Oamaru and Dunedin; K. Cultivated ground (gardens, lawns, street berms), waste land.

Naturalised from Eurasia.

Almost cosmopolitan and weedy.

Plants of D. sanguinalis in which the nerves on the lemma of the lower floret are very minutely scabrid or almost smooth, are difficult to distinguish from D. ciliaris. In D. sanguinalis the upper glume is usually < 1.5 mm, but in D. ciliaris it is 1.5-2.2 mm.

Field, T. R. O. and Forde, M. B. Proc. N.Z. Grasslands Assoc. 51: 47-50 (1990) reported that summer grass had shown a phenomenal recent increase in many places in North Id. Very aggressive and difficult to eradicate because of early development of many, very strong roots (A. E. Esler pers. comm.).