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THE AMERICAN NATURALIST [Vol. XLIX 



(b) Var. bicolor with disc 64 mm. diameter, rays only 29 

 mm. (Next to it, in the same lot, grew a plant with 

 disc diameter 38, rays 47 mm.) 



These measurements represent average heads from the 

 respective plants. A quite analogous variation was seen 

 in two plants of Ratibida cohort nifcra, growing at Boulder 

 along with the typical form (var. nov. breviradiata, rays 

 yellow, only about 10 mm. long, about half the normal 

 size). 



Torsion. — A peculiar form which appeared in our cul- 

 tures is the variety tortuosus, in which the ends of the 

 rays are twisted, as though in curl papers. This is 

 wholly unattractive, but other variations have the long 

 rays moderately curled or twisted, promising the develop- 

 ment of a series of forms analogous to the cactus dahlias. 

 As with the cactus dahlias, the rays may be rolled instead 

 of twisted; a wild form of this type may be described 

 thus : 



Hf/litii/thvs latfiatlaris var. n. angustus. Rays about 

 20, narrow, rolled, so that they are separated by wide in- 

 tervals. The rays were 36 mm. long and 5 wide (a normal 

 lenticularis ray 30 mm. long is 9 wide). Disc 26 mm. 

 ■diameter. Goodview, Colorado, July 28, 1913. 



Tnhidur Rays. — Under the heading "Number" above, 

 ■el case of completely quilled rays in a wild sunflower is 

 recorded. This peculiar modification indicates some 

 deep-seated tendency in the Composite, since it appears 

 in several genera, e. g.: 



(a) Ratibida columuifem var. n. tubularis. Rays of the 

 usual orange color, about 25 mm. long and 3.5 broad, 

 completely quilled, being hollow cylinders. Flag- 

 staff Hill, Boulder, Colorado, July 19, 1914. 



\b) Rudbeckia hirta var. tubidiforme S. H. Burnham 

 Amer. Botanist, Feb., 1914. 



(c) Gaillardia pulchella var. fistulosa (G. fishdosa Hort.). 

 Emarginate and Cleft Rays.— This is another common 



modification, also observed in other genera, as Ratibida 

 (R. columnifera var. n. incisa; rays with one or two deep 



