Kraemer : Morphology of the Genus Viola 



179 



of beneficial insects or were they developed in the first place to 

 keep out rain or injurious insects? The position of the flower 

 (more or less resupinate) would indicate that the former is accom- 

 plished by this means alone. As to whether the plant first per- 

 fected all its parts for inducing cross fertilization and then pro- 

 duced other developments for protection from injurious influences, 

 etc., are questions upon which a further morphological study of 

 the genus will undoubtedly throw some light. 



Classieicatiox oe the Genus. 



I. Froni the observations made by the author up to the present 

 time it would appear that one group is distinguished from all 

 others by possessing a nearly globular stigma with a more or less 

 lip-like appendage ; a style Avith a knee-like bend in the lower 

 portion ; long hairs on the stamens and corkscrew-shaped hairs 

 upon the spurred petal ; the spur of the stamen is 2.0-2.8 mm. in 

 length. This group comprises V. hctcrophylla (Fig. 4), V. httca 

 (Fig- 3)^ ^^' tricolor vulgaris (Fig. i), V. tricolor arvcusis (Fig. 2), 



IL The remainin^i species 



fc> 



are characterized by a stigma 



that is slightly greater in diameter than the style or is somewhat 

 globular with a beak-like projection at the apex of which the open- 

 ing for the entrance of the pollen grains is located or there may 

 be also a posterior but closed projection ; the style is either bent 

 or straight, the stamens are free from long hairs, the length of 

 spur of stamen varies in different species, and the hairs if present 

 on the spurred petal are straight. This group comprises : 



A. Spur of stamen is of the same length as anther cells : ■ V. ro- 



