1918] TuE Grasses of Illinois 303 



LAXIFLORA 



The species belonging to this group arc characterized by their soft, 

 pale green foliage. The blades in the Illinois species are edged with 

 rather long hairs or cilia and are usually pubescent on both surfaces. 

 ■ The leaves in summer are always clustered at the base of the plant 

 and are shorter here than on the culm. This cluster of leaves persists 

 in the autumn, but does not form a true rosette such as is found in the 

 next group, Dichotoma. The ligules are very short and inconspicuous. 

 The panicles in summer are borne far above the leaves; in autumn 

 they are smaller and often hidden by them. The spikelets are small, 

 always less than 2.5 mm. in length. 



Panicum xalapense H. B. K. 



(Figs. G5 and 6G) 



Hitchcock and Chase '10, 160. 



Plants in spring and early sunnner with smooth, slender culms 8 

 to 24 inches long ; sheaths densely, retrorsely pubescent with long, soft 

 hairs arising from small papillae; blades 4 to 8 

 inches long, 7 to 12 mm. broad, sparsely pubescent 

 on both surfaces, the edges ciliate, with hairs usu- 

 ally as long as those on the sheaths ; panicles few- 

 flowered; spikelets pubescent, about 2 mm. long, 

 sometimes slightly shorter. Plants in autumn more 66 



branched at the base, forming denser tufts than in ^ig- 66.— P. xal- 

 ,1 . apense, spikelet 



the sprnig. 



Thi^ species is most abundant in the southern states. It has been 

 collected only a few times in Illinois. 



JACKSON CO. Without locality, French in 1905. ST. CLAi» CO. Mascoutah, 

 Welsch. UNION CO. Anna, Seymour, Aug., 1880. 



DICHOTOMA 



The plants belonging to this group are strikingly different in 

 spring or early summer, and in autumn. The spring or vernal form 

 has several simple culms in a tuft. The panicles are few-flowered, not 

 very large, and their spikelets rarely perfect seed. In the autumn 

 a small, flat rosette is formed at the base, and the culms branch freely, 

 often resembling miniature trees. These culms often become too heavy 

 to stand erect and are found bent over or lying prostrate on the 

 ground. The dead leaves of the winter rosette are always found at 

 the base of the culms of the vernal form, if care is taken in collecting 

 the plants. The panicles borne in autumn are very much smaller than 

 those of the vernal form, and are usually included in the leaf sheaths, 

 often scarcely visible. Their spikelets always produce seed. The leaves 



