HITCHCOCK AND CHASE — NORTH AMERICAN GRASSES. 



65 



9. Cenclirus incertus M. A. Curtis. 



Cenclirus incertus M. A. Curtis, Bost. Journ. Nat. Hist. 1 : 135. 1837. " Found 

 at Sraithville in cultivated fields," south of Wilmington, North Carolina. In 

 the introduction to his enumeration of plants of Wilmington, Curtis states 

 that his new species lias been submitted to Dr. Torrey. In the Torrey Her- 

 barium, in the herbarium of Columbia University, is a sheet on which are 

 mounted a single specimen each of G. incertus and G. tribuloides, sent to Dr. 

 Torrey by Curtis, together with the following note by .Curtis : " The two plants 

 which I send were collected near the mouth of Cape Fear river, N. C, where 

 I observed them two seasons, and found them maintaining a uniform differ- 

 ence, as seen in these specimens. The one grows erect, except at the base, 

 branching freely, and attaining the height of 12-18 inches. The other is 

 decumbent, 4-6 inches long, and the spike of flowers never exceeding the 

 sheaths in length, but escaping from it laterally. It is more spiny, with 

 longer spines and more villose, with larger flowers which are more compact 

 and fewer than the tall one. If I am not mistaken the one has two perfect 

 flowers in the calyx and the other one. This small one appears to be C. 

 echinatus var. tribuloides." The published description of C. incertus applies 

 perfectly to the tall plant. The whereabouts of Curtis's own herbarium, if 

 it was preserved, is not known to us. 



Cenclirus strictus Chapm. Bot. Gaz. 3: 20. 1878. "West Coast of Florida, 

 Apalachicola and southward." In the National Herbarium is a specimen from 



w 



Fig. 15. — Cenclirus incertus. From the specimen sent by Curtis to Torrey. 



Chapman's herbarium labeled in Chapman's hand, " Cenclirus incertus, M. A. 

 Curtis, C. strictus, Chapm. in Bot. Gaz. Florida." This specimen agrees 

 well with Chapman's description but, bearing no date, it is uncertain whether 

 or not it is one of the plants from which Chapman drew up his description. 



DESCRIPTION. 



Plants perennial but apparently fruiting the first year, at length forming 

 dense clumps, glabrous as a whole ; culms 25 to 100 cm. tall, compressed, on the 

 average stouter than those of C. gracillwvus, scabrous (or rarely pubescent) 

 at the summit, ascending or erect from a decumbent base, freely branching; 

 sheaths loose and open, overlapping on the short lower internodes, often pilose 

 near the margin toward the summit ; ligule ciliate, about 0.5 mm. long ; blades 

 commonly folded, but sometimes flat, rarely stiffly flexuous as in C. gracillimus, 



