Fig. 175.—Aristida mutabilis.
Aristida mutabilis, Trin. & Rup.
This is a small tufted annual grass with simple or branched slender stems spreading at the base, and sometimes geniculately ascending and rooting at the lower nodes, 6 to 12 inches long. The nodes have dark purple rings when dry.
The leaf-sheath is glabrous, with membranous margins and long hairs at the mouth. The ligule is a row of short dense hairs.
The leaf-blade is slender, convolute, rigid, curved, and the tip ending in a sharp point, 1 to 3 inches long.
The inflorescence is a narrow panicle, cylindric, with short crowded branches, some of them remote lower down, peduncle is smooth, and rachis smooth or scaberulous; branches and pedicels are scaberulous.