No. 586] ANNUAL SUNFLOWERS 611 



Helianthus annuus L. 



(a) lenticularis (Dougl.) 

 . (b) macro car pus (D.C.) = annuus L., s. str. 

 At the same time, for ordinary purposes, it may be per- 

 missible to simply write H. lenticularis when referring to 

 the wild plant. 



3. H. aridus Rydberg. Like H. lenticularis, but 

 leaves lanceolate or narrowly deltoid, minutely toothed 

 or entire. Montana to New Mexico. Nelson calls this 

 a synonym of H. petiolaris, which it certainly is not. It 

 must be called H. lenticularis aridus (Eydb.) or H. 

 annuus lenticularis var. aridus, since it is a variable 

 form of lenticularis, which may possibly be due to cross- 

 ing with H. petiolaris, the hybrid having crossed back 

 with lenticularis. From the mode of its occurrence it is 

 nearly certain that it is not a simple lenticularis X peti- 

 olaris hybrid, petiolaris being often absent from the 

 immediate vicinity. 



To give an idea of the actual condition of affairs 

 where H. aridus occurs in Colorado, I present a synopsis 

 of the forms found at Longmont, August 30, 1914: 



(A) E. aridus type; smaller and more slender, with euneate bases to leaves. 



Disc mm. diameter, light yellow (corollas entirely dull light 



(b) Disc dark (corolla lobes dark reddish). Leaves with euneate base 

 and subentire margins ; typical aridus. Involucral bracts 

 . very broad and bristly. These rather slender plants 

 have small discs (17-21 mm. diam.) and very ample 

 rays, which are not very numerous (10-13); color of 

 rays rich orange yellow; stems lightly speckled with 

 purplish. 



(ii) Kays shorter, about 28 mm. long and 14 broad. 



(This difference in size of rays is probably environmental.) ^ 



