464 BOTANICAL GAZETTE [ JUNE 



The vitality of the plant is lessened, but its ability to bear seed in 

 abundance still remains. Economy in productive power results 

 in a prodigality of the means to perpetuate. The waste, seeming 

 or actual, is seen in the countless numbers of seeds which never have 

 a chance to germinate. The scattered plants which annually appear 

 show the need of this productiveness in order to obtain a few that 

 can overcome the adverse conditions. 



Aside from any effect which the increase of heat and light may 



it advantageous to diminish the exposed surface, it is plain that the 

 essential organs of reproduction are withdrawn from such effects 

 far more in cleistogamy than in chasmogamy. As the name implies, 

 these organs are hidden. But there is also a further tendency in 

 many cases of cleistogamy to withdraw the perianth, or protective 

 organs, from the direct effect of the sun's rays. L. canadensis is an 

 example of the former tendency, L. spuria and L. agglutinans of 

 the latter. These two species, as already stated, bend their peduncles 

 down to produce their flowers or perfect their fruit beneath the sur- 

 face of the ground. Other well-known examples of this are the 

 milkworts, Polygala polygama Walt, and P. paucifolia Willd., bearing 

 their flowers of this kind on subterranean runners. In the violets, 

 where cleistogamy is so prevalent, the peduncles of the summer 

 (usually apetalous) flowers are generally much shorter than those of 

 the large petaliferous blossoms in spring. The flowers are more 

 or less withdrawn from the light and shaded by the much enlarged 

 leaves of the summer growth, or they may be borne on stems so 

 shortened or declined as to be hidden under fallen leaves or buried 

 in soft humus. The production of the closed flowers under such 

 conditions may be due to a diminished intensity of light, as far as 

 this has a bearing on them. Experiments like those of Vochting 



more 



than the reproductive organs. Chasmogamous flowers mav be 

 made deistogamous in this way. The violets are quite variable 

 in their relations to light, many of them being on the borderland 

 between shade-loving and light-loving plants. The majority of 

 our wild species bear their petaliferous flowers in the earlier part of 

 their season of activity, those of the woods before they are strongly 



