. California grasslands and range forage grasses. Grasses; Forage plants. 31. THREEAWNS (ARISTWA) Threeawns are annuals or perennials, with slender, often wiry culms, tufted or branching from the base; spikelets nar- row, the glumes acuminate or awn- tipped; floret with a needle-like callus at base; lemma indurate, convolute, bearing a prominent 3-cleft awn, no line of de- marcation between lemma and awn. There are 13 threeawns in California, but only two species, one annual and the other perennial, occur extensively on range lands. (Fig. 95.) Although found on a variety of sites, threeawns us
. California grasslands and range forage grasses. Grasses; Forage plants. 31. THREEAWNS (ARISTWA) Threeawns are annuals or perennials, with slender, often wiry culms, tufted or branching from the base; spikelets nar- row, the glumes acuminate or awn- tipped; floret with a needle-like callus at base; lemma indurate, convolute, bearing a prominent 3-cleft awn, no line of de- marcation between lemma and awn. There are 13 threeawns in California, but only two species, one annual and the other perennial, occur extensively on range lands. (Fig. 95.) Although found on a variety of sites, threeawns usually occupy dry, rocky soils of the valley, foothill and desert ranges, especially in the central or southern part of the state. They are earlier in the suc- cession of grasslands than most forage species and frequently become abundant on depleted ranges. Under proper man- agement they usually give way to the more desirable needlegrasses with which they are commonly associated (10). Most threeawns are grazed with fair relish when young, and where more palat- able plants are not available they furnish Arlstida aligantha Anstido homuloso Hilario rigido Andropogon borbinodii. Fig. 95. Distribution of prairie threeawn (Aristida oligantha), Arizona threeawn (A. hamulosa), big galletagrass (Hilaria rigida), and cane beardgrass (Andropogon barbinodis). limited forage on early ranges. The hard, sharp florets with the three-pronged awns become troublesome to livestock as soon as the seed heads dry. After the seeds of perennial threeawns are cast the dry fo- liage is cropped limitedly in late winter and early spring; but with the coming of autumn rains the mixture of young green shoots induces livestock to graze this feed rather closely. Chemical analyses indi- cate the nutritive value of threeawns to be fair at most growth stages, but the fiber content is high (39). Grazing ani- mals aid in distributing the heavy seed crops by transporting them through at- tachment of awns to the wool
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Keywords: ., boo, bookcentury1900, booksubjectforageplants, booksubjectgrasses
