The Morphology of the Genus Viola 



* 



By Henry Kraemer 



undertook, at the su^rc^estion of 



A few years ago the author 

 Professor Arthur Meyer, Marburg, Germany, tlic study of the two 

 forms of Vio!a tricolor L., which are rather common in certain 

 parts of Germany, with the view of this study forming the basis 

 of a scientific monograph on the genus Viola. The great neces- 

 sity for such a work is expressed in Engler and Prantl's " Die 

 natiirhchen Pflanzenfamihen " as a " dringende Notwendigkeit." 



The writer has examined and compared certain parts of about 

 30 species of this genus, most of which are found in the United 

 States. Special attention has been devoted to the character of 

 style and stigma, stamen, hairs upon stigma, stamens and petals, 

 shape and size of pollen grains and bracts with mucilage-secreting 

 hairs. The results of the study thus far made arc given at this 

 time with the reservation to change certain details as further study 

 may suggest, since there is so much chaos in the genus that one 

 hesitates to make positive statements with regard to the characters 

 of the different species. 



H ^ 



Characters of the Genus. 



The genus is characterized, so far as the writer's studies go, by 

 herbaceous, annual, biennial or perennial plants, which are either 

 caulescent or acaulescent. Stolons or rhizome-like products may 

 be present or absent. The arrangement of the leaves in the acau- 

 lescent forms is basal, whereas in the caulescent, they are alter- 

 nate, the disposition above the cotyledons var>ang from \ and 

 1 to |. The leaves, apparently in all cases, consist of lamina, 

 petiole and stipiilae. The lamina, stipulae, bracts and cal)'x all 

 appear to possess characteristic mucilage-secreting hairs at the 

 anex and at the apices of the divisions. t On the stem, lamina, 



* Read at the annual meeting of the Society for Tlant Morphology and Physiology, 



Dec. 28, 1S98. 



I Already described in Tnaugural-Disscrtation on Viola Iricolorl... Marburg, 1897. 



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