﻿Vail: Studies in the Asclepiadaceae 177 



very close to some narrower leaved forms of Asclepias Mexicana. 

 A specimen of Dr. Rusby's collection of 1880 from the neighbor- 

 hood of Santa Fe, N. Mex., in Herb. U. S. Nat. Mus., is consider- 

 ably lower than any of the specimens mentioned above, is less than 

 2 dm. high and more bushy than any of the plants enumerated here. 



The A. verticillata,r\o. 1078 of the Mex. Bound, collection, is 

 undoubtedly the same as Hartweg's plant, and I believe is also 

 the plant described as A. galioidcs H.B.K. and neither are con- 

 nected with A. verticillata except as to their verticillate leaves and 

 small white flowers. A close study of the flowers of A. verticillata 

 will reveal characters which do not belong to those of A. galioidcs. 



The hoods in A. verticillata are nearly as truncate at the base 

 as at the summit, and have a very noticeable involute angle or 

 lobe on the ventral margins. On the contrary, Hartweg's speci- 

 men and with it all the so called A, verticillata var. subverticillata 

 from the Southwest have hoods which are rounded at the summit, 

 with infolded ventral margins and a gradually decurrent base which 

 is but slightly truncate. 



In E. Fournier's study of some Mexican Asclepiads (Ann. Sci. 

 Nat. VI. 14: 373. 1882) two forms are given of the species as 

 occurring in Mexico, preceded by a general description after the 

 habit of many foreign botanists. Under " Foliis angustioribus," 

 var. a galioidcs Kunth is included all the North American ma- 

 terial, apparently based on the plate in Hooker, Fl. Bor. Am. 2 : 

 54. //. 144. 1834, which is undoubtedly the true A. verticillata 

 (though the enlargement of the hood is a very bad one) and is the 

 only reference to the North American forms, for the other speci- 

 mens given are Lindheimer, Fasc. Ill, no. 456* and Fasc. IV., 

 no. 657 ; Fendler, no. 694; Parry and Palmer, no. 584 from San 

 Luis Potosi; Hartweg, no. 216; Bonpland, no. 4304 from Lake 

 Cuses, Mexico; most of which are forms of A, galioidcs H.B.K. 



Under " Foliis latioribus " var. ,1 Mexicana Cav. is all the ma- 

 terial which we know as Asclepias Mexicana, a species which oc- 

 curs from Idaho to Mexico and of which a very good plate is given 

 in Cavanilles, Icones, I : 42. pi. $S. 1791. 



*For this number see Asclepias subvertitiilnta. 



