'■^^^^ CONCLUDING EEMAKKS, Chap. IX • 



England as those of 0. muscifera, which cannot fer- 

 tilise itself and is imjierfectly fertilised by insects, so 

 that a large proportion of the flowers drop off unim- 

 pregnated. Ophrt/s aranifera is found in hirge numbers 

 in Liguria, yet Delpino estimates that not more than 

 one out of 3000 flowers produces a capsule.* Mr. 

 Cheeseman saysf that with the New Zealand Ptero- 

 sUjlis truUifoUa much less than a quarter of the flowers, 

 which are beautifully adapted for cross-fertilisation, 

 yield capsules ; whereas with the allied Acianthus 

 sindairii, the flowers of which equally require insect- 

 aid for their fertilisation, seventy-one capsules were 

 produced by eighty-seven flowers ; so that this plant 

 must produce an extraordinary number of seeds ; never- 

 theless in many districts it is not at all more abundant 

 than the Pterostylis. Mr. Fitzgerald, who in Aus- 

 tralia has particularly attended to this subject, remarks 

 that every flower of Thehjmitra carnea fertilises itself 

 and produces a capsule ; yet it is not nearly so common 

 as Acianthus fornicatus, " the majority of the flowers 

 of which are unproductive. Phajus grandifoUus and 

 Calanthe veratrifolia grow in similar situations. Every 

 flower of the Phajus produces seeds, only occasionally 

 one of the Calanthe, yet Phajus is rare and Calanthe 

 common." 



The frequency with which throughout the world 

 members of various Orchideous tribes fail to have their 

 flowers fertilised, though these are excellently con- 

 structed for cross-fertilisation, is a remarkable fact. 

 Fritz Miiller informs me that this holds good in the 

 luxuriant forests of South Brazil with most of the 

 Epidendreae, and with the genus Vanilla. For instance. 



* ' ■ 



Ult. Osservaz. sulla Dico- f Tiausact. New Zealand Inat. 



gaima,' part i. p. 177. vol. vii. 1875, p. 351. 



