208 POACE^. 



Var. Nuttallii Tluirb. .1. hnujisda Steud. Syn. PI. Gram. 420 

 (1855). 



Culms 15-30 cm. long, rays in twos and threes, the lower flexu- 

 ose, the upper uppressed ; awns ()-8 cm. long. 



New ^Icxico, Fendhr 987; Idaho, F. E. Wilcox in 1883. 



20. A. ramosissima Engelm. A. (Jray, Man. Ed. 5:G18 (1807). 

 Var. unisefa and uniarisfafa Engelm. 



A diffusely branched annual, 12-40 cm. high, the main inter- 

 nodes naked. Sheaths mostly shorter than the internodes; ligule 

 very shortly ciliate; blades involute, setaceous, 3-0 cm. long. Pan- 

 icle racemose, 3-8-llowered, 4-8 cm. long; first glume of the spike- 

 let 3-nerved, 12-15 cm. long, second equal or a little longer, 5- 

 nerved; floral glume nearly as long -is the second glume; awns not 

 jointed, the lateral ones erect, 1-4 mm. long or shorter, the central 

 hook-recurved at the base when dry, 2-3 cm. long. 



Illinois, Jical 31). 



Dry prairies, Kentucky, Illinois, and Missouri. 



27. A. dichotoma Michx. Fl. Bor. Am. 1:41 (1803). Ciuio- 

 pogon dichotomus Peauv. Agrost 32, I. 8, f. 7 (1812). 



A tufted erect or ascending annual, 30-00 cm. high. Culms 

 slender, dichotomously branched for most of their length, nodes 

 tumid, internodes naked, as their leaf-sheaths enclose the branches. 

 Sheaths less than half the length of the naked internodes; ligule 

 very short; blades involute, setaceous, those from the sterile shoots 

 10-20 cm. long. Panicles termiiuil and lateral, simi)le, very nar- 

 row, 3-8 cm. long. Spikelets with 1-nerved equal empty glumes, 

 about 7 mm. long, or the lirst a little shorter, scabrous on the 

 keels ; floret 5-0 mm. long, the erect lateral awns minute, the mid- 

 dle one reflexed and twice coiled when dry; about the length of the 

 spikelet. 



Connecticut, PvingJe; Massachusetts, Cooht/j Delaware, Clark 

 1910; District of Columbia, McCarfhy, Vasey for U. S. Dept. 

 Agricul. 237. 



Dry sandy or gravelly soil from Elaine to Texas. 



Var. Curtissii A. Gray, Man. Ed. G: 040 (1890). 



