38 TRIANDRIA, MONOGYNIA. 



35. Cenchrus, Gen.pl. 1574. (Graminex.) 



Involucrwn laciniate, echinate, 3 — 4 flowered. 

 Calix 2-valved, 2-flowered, 1 fertile the other 

 sterile. Style bifid, (sometimes 2). 



echinatus. If C. culm ancipital, leafy, branched. Leaves lan- 

 ceolate, nerved, smooth. Sheath smooth. Spike 

 lateral and terminal. Involucrums alternate lan- 

 ceolate echinate pubescent, villous internally. 

 Cal. smooth 2-valved, 5-nerved, 1,2, 3, flowered. 

 Cor, glume 2-valved, longer than the calix. Stam, 

 3. Seed one round. Muhl. 

 Cenchrus tribuloides. Bart. Prod. Fl. Ph. 



Cockspur-grass. Hedge- h og -grass. 



There is some confusion between this species and C. tribu- 

 loides of Michaux. The plant just described, I have till lately 

 mistaken for the C. tribuloides, and so called it in my Pro- 

 dromus ; but, having since compared it with the C echinatus 

 of Willdenow (a specimen of which I have in my herbarium, 

 marked with his own hand) ; and having received a specimen 

 of the C. tribuloides, from Mr. Nuttall, which be collected on 

 the sea-shore, Cape May, I find that the plant growing in this 

 neighbourhood is the echinatus, though the spike is neither 

 so long nor so dense as in the European plant. The C. tribu- 

 loides, is, I suspect, confined altogether to the sea-coast. The 

 most striking discrepancy of these two similar species, is the 

 white pubescence on the margin of the sheath, and the dense 

 white villous glumes, in the C. tribuloides, while the C. echi- 

 natus is destitute of both. The plant described by Mr. Elliot 

 under the name of tribuloides, appears to be the same brought 

 by Mr. Nuttall, from Cape May. I have already said this is 

 not identical with the species growing so abundantly in the 

 vicinity of this city, on the Jersey side of the Delaware, unless 

 its maritime situation should create the villous pubescence, 

 which from analo ■.■-. we may admit to be probable. Close to 

 Camden, not unfrequent. In the sandy road from Kaighn's 

 point towards the Haddonfield road ; and on the high sandy 

 exposed banks of the Delaware, between Kaighn's point and 

 the ferry-house, opposite to Gloucester point; abundant. 

 Annual. August. 



