13 



Twenty years later Nuttall described his //. integrifolius, said 

 to closely resemble petiolnris, but with the lower leaves opposite 

 and the peduncles relatively short. A variety gracilis had the 

 leaves denticulate, scarcely 3-nerved, and the involucral bracts 

 acuminate.* 



In 1828 Lehmann described Helianthiis patens, peculiar for the 

 large heads (as compared with the common plant known as 

 petiolaris), the long petioles and peduncles, and the peduncles 

 fleshy toward the top. The leaves are shaped essentially as in 

 annuus, or at any rate broader than in petiolaris. This, in its 

 large heads and shape of leaf-blades, resembles our hybrid; but 

 the latter has not especially long petioles, nor are the peduncles 

 noticeably fleshy toward the top. In the long peduncles and 

 petioles, and in the large heads, it resembles H. petiolaris as 

 originally described. If patens can be separated at all from the 

 original petiolaris, it must be by the broader leaves; Nuttall says 

 of petiolaris and integrifolius both, that the leaves are "ovate or 

 ovate-lanceolate." The original petiolaris appears to have been 

 described from plants grown in Philadelphia from seed, and this 

 may have affected its character. 



It appears probable, howe\-er, that H. integrifolius is really 

 the common plant of the Rocky Mountain foothills, which we 

 know as petiolaris. The t>'pe of petiolaris may be essentially 

 identical with patens, and thus we shall have to write H. petiolaris 

 integrifolius (Nutt.) for the plant generally known as petiolaris. 

 Suppose, however, that the original petiolaris and patens are of 

 hybrid origin, though not Fi hybrids of awwz<«5 X petiolaris Auctt., 

 what will be the nomenclatural result? 



H. aridus is not, I think, a hybrid; but rather a variety of 

 H. annuus lenticiilaris. 



H. canus (Britton) Wooton & Standley is a remarkable species 

 which used to be considered a variety of petiolaris. I examined 

 a specimen in U. S. Nat. Museum from near Casas Grandes, 

 Chihuahua (£. W. Nelson). The small bran ches and stems are 

 densely covered with white pubescence; involucral bracts with 

 acuminate ends ; disc white in middle as in petiolaris. 



* Trans. Amer. Phil. Soc. X. S., 8: 366. 1841. 



