158 The Ottawa Naturalist. [December 



plant. Canadian botanists are urgently requested to study this 

 species in order to explain its mode of growth from young to 

 adult stage, and especially to demonstrate the structure oi the 

 rhizome and of the cleistogamic flowers, if such are present. 



In comparing the rhizomes of these Canadian violets with 

 European species, it is interesting to notice that there is only one, 

 V. mirabilts, which exhibits the same growth as V. rotundifolia^ 

 and that these two species are not to be considered as near allies, 

 since the furmer has the flowers light purple, the latter, on the 

 contrary, yellow. In V. odorata the rhizome is monopodial and 

 the flowers as in our acaulescent species, but there are also 

 runners, which stay above ground and which develop rosettes of 

 leaves at their apex, thus repeating the growth of the mother- 

 rhizome. The caulescent V. sylvatica and F. Riviniana agree in 

 all respects with V. pubescens and its allies, while the pseudo- 

 rhizome of V. Canadensis is readily recognized in the European 

 V. canina, stagnina, elatior and a few others, which have been 

 described by Professor Hjalmar Nilsson. ^ 



THE ROOTS. 



The primary root persists for about o ie season in these per- 

 ennial species of Viola, but is soon replaced by adventitious, which 

 in the monopodial types develop from the base of the petioles from 

 four to five together, or scattered along the internodes of the 

 stolons, as in V. primulce/alia, etc. These roots are usually of 

 two kinds : nutritive and storage, of which the latter are quite 

 common in the monopodial species of the groups A, B and C ; 

 they are not very thick, however, but possess, nevertheless, a 

 large parenchymatic tissue of the cortex with an abundance of 

 starch, and correspond well with this type of root as described by 

 Dr. Rimbach.* No contractile roots were observed. 



THE ROOTSHOOTS. 



This form of shoot has only been observed in V. pedata, as 

 described above, and we might state here, that the shoots develop 

 at the tips of the roots and that they remain in connection with 



^Acta Universitatis Lundensis. Vol. 19. 1882-83, p. 205. 

 » Berichte deutsch. botan. Gesellsch. Vol. 17. iSqg, p. 18. 



