STUDIES IN VIOLA 209 



they are at first rather long and slender peduncled and become 

 shorter late in season. The apetalous flowers are not produced 

 by transition from the petaliferous ones but appear immediately 

 in their characteristic form. 



Viola striata Ait., resembles the preceeding in the number 

 of stamens. The sepals have long auricles that are characteristic 

 of the plant. The sepals are very unequal, the inner being much 

 shorter than the two or three outer ones. The transition to cleisto- 

 gamous flowers is rather more gradual but not so much so as in 

 V. canadensis Linn. The styles and stigmas of the caulescent 

 cleistogamous flowers are usually nearly straight somewhat ex- 

 panded above or but very little reflexed. 



Viola pedata Linn., stands in a class by itself as having no 

 cleistogamous flowers. The follov.'ing key shows the relationship 

 of the proposed segregates. No species will be transferred by us 

 unless such as v\^e have examined and the number of stamens 

 determined. Moreover, no species will be mentioned in Viola 

 proper unless this fact of the presence of two stamens has been 

 determined. 



KEY TO GENERA AND SUBGENERA 



A. t'lants acaulescent, the leaves and flowers of both kinds either 

 directly from rootstock or rufiners. 



(a) Cleistogamous flowers none Genus 



Oionychion (type T'. pedata Linn.) 

 (a) Cleistogamous flowers present in summer after the vernal 



petaliferous ones Genus Viola (type V. odorata Linn.) 



(b) Rootstock thick, plants with stolons, petals blue, the 



lateral bearded Subgenus Euion (type V. odorata). 



(b) Rootstock thick, plants without stolons, petals blue,^ the 



lateral bearded -Subgenus Hesperion (type V. palmata). 



(b) Rootstocks, slender, plants from and with stolons, petals 



white or pale lilac' .Subgenus. 



Verbasculum [old Genus] (type V. prinuilaefolia Linn.) 

 A. Plants caulescent, flowers axillary. 



(a) Cleistogamous flowers present appearing after the petaliferous 

 later in the season. Plants perennial. 



(b) Stamens of the cleistogamous flowers two, petaliferous 



flowers yellow Genus Crocion (type V. pubescens Ait.) 



(b) vStamens of the cleistogamous flowers five, petaliferous 

 flowers white, purplish or blue.. Genus Lophion (tj'pe V. 



canadensis Linn.) 



1 White in Viola candidula. 



2 Viola rotundifolia Michx. with yellow flowers may perhaps form 

 another subgenus. 



