No. 539] ORIGIN OF SPECIES IN NATURE 



651 



carpa americana and Rubus cuneifolius both possess 

 white-fruited varieties. 29 



Of Solatium nigrum there exist, besides the black- 

 fruited form, one with yellow and one with green fruit. 

 Atropa Belladonna exhibits the same color forms of the 

 fruit which to us are familiar in the cultivated peppers, 

 viz., red and yellow. Finally, in shrubs which are grown 

 chiefly because of the coloring of the bark, for instance 

 Cornus stolonifera, with a red bark, there may be met 

 with forms which have a yellow bark. So numerous are 

 references to color varieties in our literature and these 

 variations are met with so often that their frequency 

 suggests facility of origin perhaps parallelled only by 

 that through which dwarf forms are produced. For 

 several years, on collecting trips in the vicinity of St. 

 Louis, Mo., all patches of Lobelia cardinalis were exam- 

 ined with particular care for white-flowered plants, since 

 they were known to exist in various parts of the United 

 States. Though these observations did not lead to the 

 desired result, Mr. 0. S. Ledman, of St. Louis, was able 

 to find on the peninsula in the northern portion of Pitts- 

 burg Lake, St. Clair Co., 111., opposite St. Louis and in a 

 locality with which I believed myself to lie thoroughly 

 familiar and had searched most carefully on several 

 occasions, some plants of Lobelia cardinalis alba. 



This would indicate that the formation of the white- 

 flowered variety had taken place recently, though the 

 possibility of transportation from other localities, 

 though improbable, is not excluded. That a white-flow- 

 ered form of Mcdicago saliva is formed as readily seems 

 likely. Various species belonging to the Leguminosae 

 possess alba varieties. De Candolle speaks of a color 

 variety, 30 and at first it was thought the specimens under 

 consideration could be classed here. Since then, how- 

 ever, there were found in the same alfalfa field several 



28 Rolfs, P. H., "Variation from the Normal," Asa Gray Bull, 8: 75, 



