Chap. VIII. CLEISTOGAMIO FLOWERS. 311 



sequently insects do not visit them ; nor if they did, 

 could they find an entrance. Such flowers are therefore 

 invariably self-fertilised ; yet they produce an abund- 

 ance of seed. In several cases the young capsules 

 bury themselves beneath the ground, and the seeds 

 are there matured. These flowers are developed before, 

 or after, or simultaneously with the perfect ones. 

 Their development seems to be largely governed by 

 the conditions to which the plants are exposed, for 

 during certain seasons or in certain localities only 

 cleistogamic or only perfect flowers are produced. 



Dr. Kuhn, in the article above referred to, gives a 

 list of 44 genera including species which bear flowers 

 of this kind. To this list I have added some genera, 

 and the authorities are appended in a foot-note. I 

 have omitted three names, from reasons likewise given 

 in the foot-note. But it is by no means easy to de- 

 cide in all cases whether certain flowers ought to be 

 ranked as cleistogamic. For instance, Mr. Bentham 

 informs me that in the South of France some of the 

 flowers on the vine do not fully open and yet set 

 fruit ; and I hear from two experienced gardeners that 

 this is the case with the vine in our hot-houses ; but 

 as the flowers do not appear to be completely closed it 

 would be imprudent to consider them as cleistogamic. 

 The flowers of some aquatic and marsh plants, for 

 instance of Ranunculus aquatilis, Alisma natans, 

 Subularia, lUecebrum, Menyanthes, and Euryale,* 

 remain closely shut as long as they are sub- 

 merged, and in this condition fertilise themselves. 



♦Delpmo,'SuirOpera,laDi8tn- vol. iii. 1825, p. 1,57. For the 



buzione dei Sessi nelle Piante,' &c. behaviour of Menyanthes in Russia 



1867, p. 30. Subularia, however, see GUlibert in 'Act. Acad. St. Pe- 



sometimes has its flowers fully tersb.,' 1777, part ii. p. 45. — On 



expanded beueatli the water, see Euryale, 'Gaidener's Chroniol(». 



6ii J. E. Smith, ' English Flora,' 1877, p. 280. 



31 



