CHAP.X. INCONSPICUOUS FLOWERS. 385 



visited must be capable of self-fertilisation, otherwise 

 they would quickly become extinct. * There is, how- 

 ever, some liability to error in forming a judgment 

 on this head, from the extreme difficulty of ascertain- 

 ing whether flowers which are rarely or never visited 

 during the day (as in the above given case of Fumaria 

 capreolata) are not visited by small nocturnal Lepi- 

 doptera, which are so numerous and are known to be 

 strongly attracted by sugar, f The two lists given in 

 the early part of this chapter support Muller's con- 

 clusion that small and inconspicuous flowers are com- 

 pletely self-fertile ; for only eight or nine out of the 

 125 species in the two lists come under this head, and 

 all of these were proved to be highly fertile when in- 

 sects were excluded. The singularly inconspicuous 

 flowers of the JFly Ophrys (0. muscifera), as I have 

 elsewhere shown, are rarely visited by insects ; and it 

 is a strange instance of imperfection, in contradiction 

 to the above rule, that these flowers are not self-fertile, 

 so that a large proportion of them do not produce seeds. 

 The converse of the rule that plants bearing small 

 and inconspicuous flowers are self- fertile, namely, that 

 plants with large and conspicuous flowers are self- 

 sterile, is far from true, as may be seen in our second 

 list of spontaneously self-fertile species ; for this list 

 includes such species as Ipomcea purpurea, Adonis 

 ffistivalis, Verbascum thapsus, Pisum sativwni, Lathyrus 

 odoratus, some species of Papaver and of Nymphaea, 

 and others. 



The rarity of the visits of insects to small flowers, 



* ' Befruchtung,' &c., p. 426. collector of Noctuw, come very 



4 Nature,' 1873, p. 433. freely to sugar, and no doubt 



t In answer to a question by naturally visit flowers :" the 'En- 



tne, the editor of an entomological tomologists' Weekly Intelligencer,' 



iournal writes " The Depres- 1860, p. 103. 

 tr i se, as is notorious to every 



2 o 



