320 CLEISTOGAMIC FLOWEES. CHAP. VIII. 



last species ; but no perfect ones were produced. Mr. 

 Scott informs me that in India it bears perfect flowers 

 only during the cold season, and that these are quite 

 fertile. During the hot, and more especially during 

 the rainy season, it bears an abundance of cleisto- 

 gamic flowers. 



Many other species, besides the five now described, 

 produce cleistogamic flowers ; this is the case, accord- 

 ing to D. Muller, Michalet, Von Mohl, and Hermann 

 Muller, with V. elatior, landfolia, sylvatica, palustris, 

 mirabUis, bieolor, ionodium, and biflora. But V. tricolor 

 does not produce them. 



Michalet asserts that V. palustris produces near 

 Paris only perfect flowers, which are quite fertile ; but 

 that when the plant grows on mountains cleistogamic 

 flowers are produced ; and so it is with V. biflora. 

 The same author states that he has seen in the case 

 of V. alba flowers intermediate in structure between 

 the perfect and cleistogamic ones. According to M. 

 Boisduval, an Italian species, V. Ruppii, never bears 

 in France " des fleurs bien apparentes, ce qui ne 1'em- 

 peche pas de fructifier." 



It is interesting to observe the gradation in the 

 abortion of the parts in the cleistogamic flowers of 

 the several foregoing species. It appears from the 

 statements by D. Muller and Von Mohl that in V. mi- 

 rabttis the calyx does not remain quite closed ; all five 

 stamens are provided with anthers, and some pollen- 

 grains probably fall out of the cells on the stigma, 

 instead of protruding their tubes whilst still enclosed, 

 as in the other species. In V. hirta all five sta- 

 mens are likewise antheriferous ; the petals are not 

 so much reduced and the pistil not so much modified 

 as in the following species. In V. nana and elalior 

 only two of the stamens properly bear anthers, but 



