Chap. X. INCONSPICUOUS FLOWERS. 389 



than those from self-fertilised flowers; and this was 

 likewise the case to a certain extent with Vandellia. 

 As therefore no species which at one time bore perfect 

 though small and inconspicuous flowers has had all its 

 flowers rendered cleistogamic, I must believe that 

 plants now bearing small and inconspicuous flowers 

 profit by their still remaining open, so as to be occa- 

 sionally intercrossed by insects. It has been one of 

 the greatest oversights in my work that I did not 

 experimentise on such flowers, owing to the difficulty 

 of fertilising them, and to my not having seen the 

 importance of the subject.* 



It should be remembered that in two of the cases in 

 which highly self-fertile varieties appeared amongst 

 my experimental plants, namely, with Mimulus and 

 Nicotiana, such varieties were greatly benefited by a 

 cross with a fresh stock or with a slightly different 

 variety ; and this likewise was the case with the 

 cultivated varieties of Pisum sativum and Lathyrus 

 odoratus, which have been long propagated by self- 

 fertilisation. Therefore until the contrary is distinctly 

 proved, I must believe that as a general rule small and 

 inconspicuous flowers are occasionally intercrossed by 

 insects ; and that after long-continued self-fertilisation, 



* Some of the species of Sola- On the other hand, the flowers of 



num would be good ones for such the common potato (S. tuberosum), 



experiments, for they are said by though they do not secrete nectar 



H. Midler (' Befruchtung,' p. 431) (Kurr, ' Bedeutung der Nekta- 



to be unattractive to insects from rien,' 1833, p. 40), yet cannot be 



not secreting nectar, not producing considered as inconspicuous, and 



much pollen, and not being very they are sometimes visited by 



conspicuous. Hence probably it Dipteru (Midler) and, as I have 



is that, according to Verlot (' Pro- seen, by humble-bees. Tinz- 



duction des Varie'tes,' 1865, p. 72), mann (as quoted in 'Gardeners' 



the varieties of " les aubergines Chronicle,' 1846, p. 183) found 



et les tomates " (species of Sola- that some of the varieties did not 



num) do not intercross when they bear seed when fertilised with 



are cultivated near together ; but pollen from the same variety, but 



it should be remembered that were fertile with that from an* 



these are not endemic species. other variety. 



