HITCHCOCK — REVISIONS OF NORTH AMERICAN GRASSES. 121 



described as glabrous, wbile in Isachne arundinacea, the only other species it could 

 be, they are scabrous. 



Isachne ? dubia Kunth, Rev. Gram. 1 : 42. 1829. Based on Panicum dispermum Lam. 

 The question mark inserted by Kunth is accounted for by his note, "In herbario 

 Richardi non amplius suppetit." 



Isachne disperma Doell in Mart. PI. Bras. 2 2 : 274. 1877. Based on Panicum di- 

 spermum Lam. 



DESCRIPTION. 



Aspect of plant as in I. arundinacea; sheaths glabrous or rarely papillose-hispidulous; 

 ligule hairs as much as 2 mm. long; blades on the average larger than in I. arundinacea, 

 glabrous, scabrous toward the apex; panicles as much as 20 cm. long, the branches and 

 branchlets spreading, the spikelets in twos or threes at the ends of the branchlets, the 

 panicle thus more open and flowered more equally throughout than in I. arundinacea, 

 the spikelets not strongly aggregate toward the periphery; spikelets slightly over 1 

 mm. long; glumes and florets glabrous. 



DISTRIBUTION. 



Mountain woods, Lesser Antilles. 

 Leeward Islands: St. Kitts, Britton & Cowell 395. Guadeloupe, Duss 3189. 



Dominica, Eggers 1056; Jones 38. 

 Windward Islands: Martinique, Duss 1311. Grenada, Broadway 76. 

 Tobago: Amer. Gr. Nat. Herb. 597. 



Explanation of Plate 32.— Isachne duperma. Specimen from St. Kitts, Britton & Cowell 395. 

 Natural size. 



