Flora of New Zealand Series

smooth witchgrass

Almost glabrous, tufted summer annuals. Leaf-sheath light green to commonly purplish, submembranous, flattened, rounded, glabrous. Ligule 1-2 mm, a membranous densely ciliate rim. Leaf-blade 7-30 cm × 3-5.5 mm, ± rounded at base, narrowed above, dull green to purplish, glabrous, abaxially slightly keeled, adaxially channelled, rarely with scattered, long, fine hairs; margins finely scabrid, tip acuminate. Culm 20-60 cm, often geniculate at base, almost prostrate and rooting at lower nodes, or ascending or ± erect, internodes glabrous or slightly hairy near nodes. Panicle 8.5-35.5 × 1.5-7-(15) cm, usually not fully emergent from leaf-sheath; branches fine, smooth, ascending to later spreading, branchlets and pedicels shorter, finer, scabrid, tipped by ± close-set spikelets. Spikelets 2.8-3.3 mm, glabrous, light green to purplish, narrow elliptic-oblong, much narrowed to acute tip. Glumes very unequal; lower c. 1 mm, ovate, sometimes slightly notched at broad acute tip, 3-nerved, upper = spikelet, (7)-9-nerved, elliptic, tapering above to acute tip. Lower floret Ø: lemma slightly < upper glume, (7)-9-nerved; palea shorter and much narrower than lemma, 2-keeled, keels glabrous. Upper floret ⚥: lemma c. 2 mm, elliptic, subacute, faintly striolate, glabrous, shining, light cream; palea narrower; anthers 1-1.5 mm; caryopsis c. 1.5 × 0.8 mm.

N.: North and South Auckland (common in Waikato), occasional further south. Weed of crops (especially maize, onions), and disturbed soil in orchards, gardens, roadsides, waste places and pasture.

Naturalised from North America.