58 BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 



Low perennials, with extensively creeping scaly rhizomes, erect, 

 rather rigid stems, and short, dense, rather few-flowered panicles. 

 Species about six, in salt marshes of the coast and interior in America, 

 one extending to Australia ; three species in the United States, one 

 widely distributed and two confined to Texas and northern Mexico. 



Type species : Uniola spicata L. 



Distichlis Raf., Journ. de Phys. 89: 104. 1819. Distichlis maritima is indi- 

 cated as the type by Rafinesque, who Drives Uniola spicata L. as a synonym. 



Brizopyrum Presl, Rel. Haenk. 1: 280. 1830. Presl describes five species, of 

 which the first two belong to Distichlis. None is figured. The first species, 

 B. boreale (DistichUs. spicata), is selected as the type. 



The common species, Distichlis spicata (L.) Greene (fig. 24), is 

 found along both coasts and in salt or alkali spots in the interior, 

 and extends southward to South America and to Australia. It is an 

 erect, gregarious grass usually not more than a foot high, with pale 

 spikelets, the staminate having a softer texture than the pistillate. 

 The common name is salt or alkali grass, though these names are some- 

 times applied to other species. In general it has little value for 

 forage but in the interior basins, such as the vicinity of Salt Lake, it 

 is utilized for grazing when better grasses are not available. The 

 large amount of salt or alkali may cause digestive disturbances. 

 This species is variable, and two forms have been distinguished as 

 species, D. stricta (Torr.) Ryclb. and D. dentata Rydb., both from 

 the Western States. 



The two species of the Southwest are not well known. Distichlis 

 texana (Yasey) Scribn., a larger grass than D. spicata, with less 

 compressed spikelets and a long, narrow, loose panicle, is found from 

 Texas to Durango. Distichlis multinervosa (Yasey) Piper is an 

 anomalous species from western Texas known only from the type 

 collection. It differs in having a villous rachilla and 7-nerved mem- 

 branaceous lemmas, rounded on the back and villous on the lower 

 part, and in the 2-lobed palea. 



18. UNIOLA L. 



Spikelets 3 to many flowered, the lower one to four lemmas empty, 

 the rachilla disarticulating above the glumes and between the florets ; 

 glumes compressed-keeled, rigid, usually narrow, nerved, acute or 

 acuminate, or rarely mucronate ; lemmas compressed, sometimes con- 

 spicuously flattened, chartaceous, many-nerved, the nerves some- 

 times obscure, acute or acuminate, the empty ones at the base usually 

 successively smaller, the uppermost usually reduced; palea rigid, 

 sometimes bowed out in the winged keels. 



Perennial, rather tall, erect grasses, with flat or sometimes convo- 

 lute blades and narrow or open panicles of compressed, sometimes 

 very broad and flat spikelets. Species nine, all North American, 



