Growth pattern Hilaria rigida is a long-lived, shrubby or bushy, clumping
perennial grass producing coarse, erect stems reaching in maximum height. Clumping results from spread by
tillers or short
rhizomes. Clumps of leaves are wide. Seeds fall when mature, but their stalks persist, sticking out from the clumps like zigzagging wires, by which the plant can be identified at a distance. It is drought tolerant and very fast growing after rains. It typically undergoes two major growth periods, one after winter rains, the other after summer monsoons. It is reported to be more effective than many other desert plants at extracting water from the soil during dry periods.
Roots, stems, and leaves Roots are shallow and radiate outward from the base of the plant. Fuzzy to wooly stems are stiff, heavy, and coarse, from long. The stems are unusual among grasses in that they are solid, even between the nodes, whereas most grasses have hollow stems. They can be either erect or lying on the ground (
decumbent). Stems have
nodes that are lined with long, sometimes curly hairs. Leaf blades are coarse and firm, fairly wide, and almost straight, from grayish to blue-green, sometimes with light wooly fuzz, and have curly hairs and edges that are rolled upward. They are from long. Leaves are attached either to the base of the plant or along the upright stems that bear the heads of seeds.
Inflorescence and fruit The
inflorescence is a series of hairy or brush-like rectangular spikelets, occur in clusters of three, between . The grass produces relatively few viable seeds and spreads mostly by its
tillers and sometimes via
rhizomes. The inflorescence stalk persists after the seeds drop, sticking out of the clump of leaf blades like stiff, wavy wires. It blooms between December and January according to some sources, from May to June in the Mojave Desert according to others, and from February through June in the Mohave Desert according to others. The variation may result from a paucity of information on
germination characteristics (as of 2014). Seedlings rarely become established. The head of seeds is a spike of seeds with much chaff. Spikes are long. ==Ecology==