HITCHCOCK AND CHASE — NORTH AMERICAN GRASSES. 



69 



relatively short-spined form represented by the type of G. pauciflorus. A 

 single collection {Hitchcock in 1904) from Sarita, Texas, is this short-spined 

 form. In the West Indies this species and G. tribuloides approach each other 

 closely. Only specimens from the vicinity of Habana, possibly introduced, are 

 like continental specimens. The one from the Bahamas and the one from 

 Jamaica, particularly the latter, are like G. tribuloides in habit, but they have 

 the smaller burs of C. pauciflorus. 



Genchrus spinifex Cav., 1 described from Chile, has been referred to "C. tribu- 

 loides " as a synonym. The type has not been examined. Cavanilles's descrip- 

 tion of the " calix communis " [involucre] as " integerrimus " does not apply 

 to any known species of Genchrus. A species with interlocked lobes might, at 

 first sight, give the impression of an uncleft body, but the most superficial ex- 

 amination of G. pauciflorus would reveal the lobes. The crude illustration 

 shows an uncleft body with thick spines. The relatively short, broad blades 

 described and figured are not those of C. pauciflorus. In the National Her- 



M 



fill/*:! 

 WW 



Fig. 18. — Genchrus pauciflorus. From Hitchcock 13532 ; typical of the species. 



barium there are four specimens of G. pauciflorus from southern South America 

 (though none from Chile), but there is nothing that agrees with Cavanilles's 

 description and plate. The grasses of that region are as yet but little known. 

 The identity of G. spinifex has been carefully considered, and it seems certain 

 that it can not be C. pauciflorus. Another species described from Chile which 

 we are unable to identify is C. muricatus Phil. 2 (not Linnaeus, 1771). This 

 also is' described as having entire involucres. In any case Philippi's name is a 

 homonym. 



DISTRIBUTION. 



Sandy open ground, and along railway embankments, Massachusetts to Flor- 

 ida, west to Oregon and California, ascending to 2,000 meters in the Rocky 

 Mountains, south throughout Mexico, mostly on the plateau, rare in the tropical 

 part of the continent, and appearing again from southern Brazil to Argentina ; 

 also in the West Indes. 

 Ontario : Leamington, Macoun 63. 

 Massachusetts : South Hadley, Clark in 1887. 

 Connecticut : South Glastonbury, Wilson 28. 

 New York : Erastina, Pollard in 1894. Northville, Young in 1873. 



1 Icon. PI. 5 : 38. pi. 461. 1799. 



2 Anal. Univ. Chile 36 : 202. 1870. 



