1Rbo6ora 



JOURNAL OF 



THE NEW ENGLAND BOTANICAL CLUB 



Vol. 8. July, 1906. No. 91 



THE VIOLETS AND VIOLET HYBRIDS OF THE DIS- 

 TRICT OF COLUMBIA AND VICINITY. 



(Plates 71, 72.) 



Homer Doliver House. 



During the seasons of 1904 aiul 1905, a survey of the violets of 

 this region was undertaken by the writer with the object in view of 

 ascertaining the status of certain j)eculiar forms, some already de- 

 scribed as species and others recognizetl as hybrids, and further to 

 discover if possi})le whether or not the supposed hybrids w^ere con- 

 sistent with the pure species found in their immediate neighborhood. 



A careful fiekl study was made of a large number of colonies, and 

 sets representing my collections have been placed in the herbaria of 

 the National Museum, New York Botanical Garden, Missouri Botani- 

 cal Garilen, Harvard University, Ezra Brainerd and H. D. House. 



Practically all of the characteristics peculiar to violet hybrids as 

 noted by Mr. Brainerd in recent articles, apply to those found in this 

 vicinity. Moreover, not a single hybrid was fountl but that the par- 

 ent species were immediately associated with it or were to be found 

 within a few rods. A brief review of the methods of cross-fertiliza- 

 tion of the violets shows that for two species to be crossed they must 

 not only occur in the same region but must be cohabitant with each 

 other or at most, occur within a few rods of each other. Another 

 noticeable fact is that the most remarkable hybrids and variations, 

 always occur ujion new soil, recently cleared land, embankments,, 

 along ditches, etc. — in short, in places the conditions of which are due 

 to the work of man and not nature. 



