Compilation
Helopus nubicus

Annual, tufted, 1/2 to over 2 ft. high. Culms geniculately ascending, slender to somewhat robust, rarely quite erect, few- to over 5-noded, branched from the lower or sometimes also from the middle nodes, glabrous or finely pubescent below the inflorescence. Leaf-sheaths rather loose, often thin, finely striate, quite glabrous or very finely pubescent at the nodes or also higher up or all over; ligules reduced to a line of cilia; blades linear from an equally wide or shortly and slightly contracted base, long-tapering to an acute point, from less than 1/2 to over 6 in. by 1 1/2–4 lin., thin and flaccid to rather firm and subrigid, quite glabrous or more or less minutely hairy on one or both sides (particularly the lower), smooth or slightly rough upwards, midrib slender to very fine, lateral primary nerves 3–6 on each side, slender to very fine. Panicle narrow, flaccid, 1 1/2–4, rarely up to 5 in. long, of few to up to 10 (rarely more) suberect or obliquely spreading straight or flexuous distant racemes; common axis slender, subterete, channelled, striate to angular, finely ciliolate or scaberulous upwards along the edges of the channel, otherwise glabrous or delicately pubescent; racemes peduncled (the lower with the peduncles 1/4 to up to over 1 in. long) or subsessile, 1 1/2– 1/2 in. long, terminating with a spikelet; rhachis flat on the back, from less than 1/4– 1/2 lin. wide, with a slender acute projecting midrib on the face (hence more or less triquetrous in cross-section), scabrid or scaberulous, here and there also ciliate along the angles, otherwise finely pubescent or almost glabrous; pedicels 2-nate or solitary, all very short or the longer of a pair up to 3/4 and even 1 lin. long, slender, finely pubescent with few to many fine rigid hairs from below the subdiscoid tips, the hairs up to over 1 lin. long, forming suberect beards if numerous. Spikelets 2-seriate, laterally contiguous, ovate-anceolate, long and finely aristulate-acuminate, including the acumen 2 lin. long, pale green, more or less silky; basal bead-like internode pale or one half blackish-purple, up to 1/6 lin. in diam. Lower glume reduced to a narrow membranous cupular rim around the bead; upper 5-nerved, appressedly silky, awnlet up to 1/2 lin. long. Lower floret reduced to a mucronulate valve slightly shorter than the upper glume and very similar to it. Upper floret finely punctate, up to 1 1/4 lin. long; valve with a mucro up to 3/8 lin. long. Anthers 1/3 lin. long. Grain elliptic in outline, over 6/10 by 4/10 lin., pale greenish.