,-2 The Ottawa Naturalist. [December 



diagnoses of V. mirabilis : " Vioia montana latifolia, flores ex 

 radice, semina in cacumine ferens D-ll.," and ^' Viola floribus 

 radicalibus abortientibus, caulinis apetalis seminiferis Linn." But 

 besides V. mirabilis a few other old world species of the genus are 

 known to produce cleistogamic flowers as, for instance, V. odorata, 

 silvatica, canina and persicefolia, some of which have been 

 described and figured by Professor Warming in his Manual of 

 General Botany (1895. p 546.)- The structure of the cleisto- 

 gamic flowers is not, however, identical in all the species, and in 

 regard to the North American species we have noticed some pecu- 

 liarities, which may prove useful in the distinguishing of certain 



species. 



The cleistogamic flowers remain constantly closed in the 

 species which we have examined, and the general aspect is like 

 that of V. MacQunii, figured on our Plate IV . fig. i , and the 

 flower is nodding like the perfect. The sepals are normally 

 developed and show a very prominent ciliation, but the petals are 

 merely pre5ent in the shape of small warts ; only two stamens 

 are developed, (fig. 2) and in their natural position they are closely 

 applied to the pistil. These stamens have large connectives, 

 prominently denticulate along the margins, and the anthers are 

 small and contain as usually only a few pollen-brains. The pistil 

 has a short curved style, but no proper stigma is developed. 

 These cleistogamic flowers of V. Macounii are sometimes buried 

 in the ground, but at other times they are raised above the sur- 

 face, borne on almost erect peduncles. It seems as if this varied 

 position is due to atmospheric conditions ; we have at least 

 noticed that in several other species these flowers are only buried 

 in the ground when the season is very warm and dry, while they 

 develop above ground when the atmosphere is damp and cool. 

 In Viola papilionacea the cleistogamic flowers are, thus, not 

 always underground, and they differ from those of V. Macounii 

 by having larger appendages on the sepals (fig. 5) and by these 

 being glabrous. In this species there are, also, only rudimentary 

 petals and only two stamens, which are somewhat larger than 

 those of the former species. But in V. sagittata the cleistogamic 

 flower is very much different. The appendages of the sepals 

 (fig. 8) are long and narrow: the anterior petal is plainly developed 



