318 CLEISTOGAMIC FLOWERS. CHAP. VIII 



lated development : I found on a purple variety, 

 after it had produced its perfect double flowers, and 

 whilst the white single variety was bearing its cleisto- 

 gainic flowers, many bud-like bodies which from their 

 position on the plant were certainly of a cleistogamic 

 nature. They consisted, as could be seen on bisecting 

 them, of a dense mass of minute scales closely folded 

 over one another, exactly like a cabbage-head in 

 miniature. I could not detect any stamens, and in the 

 place of the ovarium there was a little central column. 

 The doubleness of the perfect flowers had thus spread 

 to the cleistogamic ones, which therefore were ren- 

 dered quite sterile. 



Viola hirta. The five stamens of the cleistogamic 

 flowers are provided, as in the last case, with small 

 anthers, from all of which pollen-tubes proceed to the 

 stigma. The petals are not quite so much reduced 

 as in V. canina, and the short pistil instead of being 

 hooked is merely bent into a rectangle. Of several 

 perfect flowers which I saw visited by hive- and humble- 

 bees, six were marked, but they produced only two 

 capsules, some of the others having been accidentally 

 injured. M. Monnier was therefore mistaken in this 

 case as in that of V. odorata, in supposing that the 

 perfect flowers always withered away and aborted. He 

 states that the peduncles of the cleistogamic flowers 

 curve downwards and bury the ovaries beneath the 

 soil.* I may here add that Fritz Miiller, as I hear 

 from his brother, has found in the highlands of South- 

 ern Brazil a white-flowered species of violet which 

 bears subterranean cleistogamic flowers. 



* These statements are taken io tlie supposed sterility of the 



from Professor Oliver's excellent perfect flowers in this genus see 



article in the ' Nat. Hist. Review,' also Timbal-Lagrave in ' Bot 



July 1862, p. 238. With respect Zeitung,' 1854, p. 772. 



