326 PROCEEDINGS OF THE AMERICAN ACADEMY. 



that the ray pappus is never developed as in the disk flowers, but is 

 always more or less abortive, consisting of fewer, shorter, and more 

 slender bristles. Furthermore, the variation in its development seems 

 absolutely independent of any other characters either floral or habital, 

 so that varieties founded upon this character can have no more than 

 formal value. Indeed this is the view which Dr. Gray subsequently 

 took in the Synoptical Flora, i. 303. On the other hand, the form and 

 length of the pappus in the disk flowers seem more worthy of note, 

 and several plants have recently been received at the Gray Herbarium 

 which differ so materially in this regard and in their greater hbpidity 

 from the typical G. parviflora, Cav., as to call attention to the group. 

 In those plants from the Eastern and Middle States, as cited below, the 

 pubescence of the upper interuodes is not only considerably more copi- 

 ous but much more spreading, the rays are bright white and well ex- 

 serted, and the pappus scales of the disk flowers, while in length about 

 equalling the achenes as in G. parviflora, have a very different form, 

 beincr narrower and attenuate to a bristle-like apex. One of these 

 specimens, collected by Mr. H. L. Clark at Pittsburg, Pa., was for- 

 warded to Geneva for comparison with De Candolle's G. parviflora, 

 var. hispida, and has been pronounced by M. Buser identical with that 

 variety. Still a third plant of this genus quite distinct from the pre- 

 ceding has been collected upon waste land about Camden, N. J., by 

 Mr. C. F. Parker. It is characterized by considerable pubescence, 

 distinctly purple rays, and disk pappus but half as long as the achene. 

 Portions of this plant have been forwarded to Geneva and Kew for 

 comparison with Vargasia Caracasana, DC, and Galinsoga hispida, 

 Benth., and it proves identical wiih both, while garden specimens of 

 Regel's G. br achy Stephana show it with scarcely a doubt to be the same. 

 This shows that Dr. Gray was in error in regarding his G. parviflora, 

 var. Caracasana the equivalent of De Candolle's Vargasia Caraca- 

 sana. While Mr. Parker's plant from Camden, the weed-centre of 

 the United States, by no means shows this species of tropical origin to 

 be established in our country, it may well be found that a portion of 

 what has been hitherto referred to G. parviflora is this plant, espe- 

 cially as it is more or less extensively introduced in Eastern Europ3, 

 where it bears the name G. brachystephana, Regel. Summing up the 

 different forms as well as the material at hand permits, we may 

 divide them as follows. 



* Kays white, pappus of the disk flowers about equalling the achene. 

 G. parviflora, Cav. Smoothish, the upper internodes with a 

 sparing sub-appressed pubescence : pappus of the disk flowers of spatu- 



