15 



H. maximiliani rays turn brilliant scarlet on basal half; apical 



half deep orange, red along the veins. 

 H. orgyalis rays turn brilliant scarlet on rather less than basal 

 half, apical half more or less red along veins. 



On the other hand, the rays of H. decapetalus var. plenus, H. 

 annuus, H. petiolaris, Viguiera helianthoides, Taraxacum, Soli- 

 dago, Rudbeckia (golden glow), Chrysopsis, Tragopogon, Ratibida 

 and Grindelia do not turn red at all with KHO. Rays of Heliop- 

 sis scabra turn deep orange, exactly the color of the orange flush 

 on EschschoUzia petals. Helianthella quinquenervis rays show 

 no red. Helianthus giganteus (Highlands, N. C, Mrs. Wm. 

 Duane) has the longitudinal veins reddened by the KHO, but 

 there is no definite scarlet color ; evidently there is a very minute 

 quantity of the red-producing pigment. 



A watery solution of reddened rays of H. pumilus is wine or 

 cherry color; this color is completely discharged by nitric acid. 



The red (anthocyanic) variety of H. annuus gives totally 

 different reactions. The red parts of the rays turn green in 

 KHO, and bright scarlet in acid. The green is due to the bluish 

 or purplish (alkaline) state of the anthocyan pigment being 

 modified by the presence of flavone, which is yellow with alkali.* 



Thus lichens are not the only plants to be tested with chemicals 

 in order to determine affinities. We find that most (not all) 

 the perennial sunflowers, though apparently colored exactly 

 like the others, really contain something very distinct. The type 

 of Viguiera, so far as this character goes, falls with H. annuus, etc. 



If the present rather unsatisfactory generic arrangement of 

 the Helianthus- Viguiera series is changed, two courses are open. 

 One is to merge all the species in a single genus, Helianthus; 

 the other to restrict Helianthus to the annual species such as 

 H. annuus, lenticularis, cucumerifolius and argophyllus, and 

 refer the others to one or more distinct genera. On the latter 

 basis, which seems preferable, Viguiera may be extended to 



*I follow Miss Wheldale's interpretation of similar phenomena but H. H. 

 Bartlett gives reasons for doubting her explanation. I found that on adding KHO 

 to an acidulated extract of red sunflower rays a green color was produced, but the 

 margins of the green area were clear blue-purple or lilac. This appears to support 

 Miss Wheldale's theory. 



