€hap. VIII. VIOLA. 317 



Another fact is worth giving as an instance of corre- 

 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 cleistogamic 

 flowers, many bud-like bodies which from their posi- 

 tion on the plant were certainly of a cleistogamic na- 

 ture. 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 minia- 

 ture. 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 rendered 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 per- 

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

 bees, six were marked, but they produced only two cap- 

 sules, some of the others having been accidentally in- 

 jured. 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 Southern Brazil a 

 white-flowered species of violet which bears subterranean 

 cleistogamic flowers. 



* These etaternents are taken to the supposed sterility of the 



from Professor OUvrt's excellent perfect flowers in this eenns see 



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



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



