DEGENERACY OF FLOWERS. 2C1 



the permanent forms of the flowers of 0. corniculata, which I 

 at first inferred, from the wide distribution of this species, 

 must be habitually self-fertilising. From Fig. 57, a, it will be 

 seen that the corolla just protrudes from the closed sepals, 

 and always remains as a "cap," b. Of the ten anthers, five 

 are often abortive or wanting, d; the fertile anthers are 

 placed over the very short stigmas, and are bound together 

 by fine threads. These appear to play some part, but the 

 nature of their function is obscure, c. 



Impatiens fiilva and I. NoU-me-tangere have also cleisto- 

 gamous flowers. Fig. 58, a, represents 

 a bud, and h two metamorphosed sta- 

 mens. 



Lamium aviplexicaule will furnish 

 another example of cleistogamy. This Fig. 58.— a, cieistogamous 



, 11 n 1 ' ^ ^ T re flower-bud of Impatiens 



genus has usually liowers higniy diiieren- fuiva; b, stamens (after 



tiated, and adapted to insect fertilisation. euneti). 



That the cieistogamous flowers of this, as of all other species, 



are degraded forms of the normal kind is obvious from the 



presence of the " lip," as well as by there being four and 



didynamous stamens. The style elongates ver}' much, and 



under the pressure of the closed 



summit of the corolla becomes bent, 



so that the stigmas lie between the 



anther-cells, and thus readily become 



fertilised. Fig. 59, a, represents a 



flower-bud ; 6, the corolla in section ; 



and c, the pistil removed. This f>k- 59.-<i, cieistogamous flower- 



'^ _ ^ bud of Art »H I (/m ainplcxicaule; b, 



condition of cleistogamy is found in vertical section of same; c, pistil. 



the earlier-flowering plants, so that it is probably a mere 

 result of check through a colder temperature. 



Salvia clandestina may be compared with the hist 

 described, as it is a self-fertilising form of, perhaps, S. pra- 



