208 AMERICAN MIDLAND NATURALIST 



important characters of distinction in these cleistogamous flowers 

 themselves. 



During the past season particularly, and in fact for nearly 

 a decade past, this interest in the apetalous flowers was main- 

 tained by us. Though not a great number of individual species has 

 as yet been examined, in every one of the groups it has been found 

 that e. g., acaulescent violets including, the white violets such as 

 V. lanceolata, V. primulaejolia, V. hlanda, V. incognita, have 

 uniformly, as far as examination of their cleistogamous flowers 

 was made, two fertile stamens, with occasionally the presence 

 of a very small abortive petal or two, as in case of V. cucullaia. 

 The solitary abortive petal is usually the keel, or lower petal. 

 The other petals and stamens are represented if at all as minute 

 processes like small stiped capitate glands, found in their regular 

 positions with respect to the more or less equal sepals. 



The caulescent violets represent three groups. The pancies 

 which are annuals, biennials or winter annuals, have no cleisto- 

 gamous flowers. Viola eriocarpa Schwein {Viola scahriuscula 

 Schwein) and Viola pubescens Ait., have subequal sepals and only 

 two stamens in their apetalous summer flowers. Viola canadensis 

 Linn., Viola rostrata Pursh, Viola striata Ait., have five fertile 

 stamens in their cleistogamous flowers. The first of these does 

 not produce these flowers until very late in the season and then 

 the transition from petaliferous to apetalous ones is a rather 

 gradual process. The petals become gradually smaller and finally 

 disappear completely, one or several at a time. The sepals are 

 short and seem to be open when the capsule is fertilized. Even 

 late in fall there may often be found what seem to be cleistogamous 

 flowers with one to several minute whitish petals. In fact the 

 budlike closed cleistogamous flowers of this species do not seem 

 to be as fertile as they are in the rest of the violets, and appear 

 to fall off aborted before producing seed. They are reproduced 

 at the end of the shoots and are short-stalked apical and some- 

 times in old leaf axils. 



The cleistogamous flowers of Viola rostrata are among the 

 first to appear and continue to develop until winter. The sepals 

 are at first and before fertilization somewhat unequal. The 

 peduncle is not bent and this is the case in all the plants of the 

 caulescent group. The stamens are five in number. They grow 

 usually from the ends of the stems which do not elongate much; 



