YELLOWSTONE NATIONAL PARK 



(yellow) (yellow) 



61 



SUNFLOWER 



DWARF SUNFLOWER 



Sunflower (Helianthus) . There are several sorts 

 of wild sunflower in the Park, but they are similar in 

 general appearance. Their stems are rather stout, 

 ranging in height from about two to four feet, accord- 

 ing to species. The leaves are opposite, usually lance- 

 shaped or very narrowly oval. The flowers average 

 between two and three inches in diameter, with broad 

 yellow rays and either yellow or dark brown disk. 

 The common sunflower of our backyard gardens is here 

 in a dwarf form, usually about two feet high; it is 

 found only at the lower elevations. The sunflowers 

 come into bloom in July and remain until frost. 



Dwarf Sunflower (Helianthella) . This plant is 

 closely related to the true sunflowers, but has several 

 marked points of difference. Most of its leaves are in 

 a long-stemmed basal group; they are quite large, 

 rough, and broadly and bluntly arrow-shaped. The 

 flower-stems are about a foot or eighteen inches tall, 

 with a few smaller leaves. The flower-heads are borne 

 singly; they are typical sunflowers, with yellow rays 

 and dark disks. Range is restricted to the lower al- 

 titudes; the plant is especially abundant on the hill- 

 sides around Mammoth Hot Springs. Blossoming be- 

 gins in June and ends early in July. 



