978 



Composite 



Actinomeris 



55 



Map 2138 



Helianthus decapetalus L 



50 



Map 2139 



Helianthus tuberosus L 



14. Helianthus decapetalus L. Thinleap Sunflower. Map 2138. This 

 sunflower is usually found in dry woods with oaks and less frequently with 

 sugar maple. It is rarely found in the open or in moist locations. Fre- 

 quent to infrequent throughout the state. 



Cent. Maine, w. Que. to Minn., southw. to Ga., Tenn., and Mo. 



15. Helianthus tuberosus L. Jerusalem Artichoke. Map 2139. This 

 is one of our most common sunflowers and is frequent throughout the state. 

 It grows in the open in moist soil along streams, ditches, and roadsides. 



This species is quite variable and gives more trouble in naming than 

 any other species. Some authors rely upon the tuberous roots for identifi- 

 cation. In September, 1936, which was a dry year, I dug in our garden 25 

 specimens and then went to an old fence row and dug many more and I 

 failed to find a single tuber. I regard the dark color of the bracts and the 

 pubescence on the lower surface of the leaves as the most reliable characters 

 for the identification of this species. The shape and length of the bracts 

 are too variable to consider although in some instances they are quite 

 characteristic and are confirmatory characters. 



N. A. east of the Rocky Mts., according to Watson. 



16. Helianthus strumosus L. Map 2140. This is a frequent sunflower 

 in the lake area in dry woods and in dry sandy soil along roadsides and 

 elsewhere in a similar soil. South of the lake area it becomes rare, local 

 or absent. 



Specimens of this species with short petioles and the blades of the leaves 

 nearly round at the base closely approach Helianthus divaricatus. In sep- 

 arating the two species I have relied upon the convergence of the lateral 

 veins of the leaves. In this species they always converge slightly above the 

 base while in Helianthus divaricatus they converge at the base of the blade. 



Maine, Ont. to Minn., southw. to Ga. and Ark. 



9215. ACTINOMERIS Nutt. 



1. Actinomeris alternifolia (L.) DC. (Verbesina alternifolia (L.) 

 Britt.) YELLOW IRONWEED. Map 2141. Infrequent to frequent or locally 



