450 FERTILISATION OF FLOWERS. [1862. 



of Muller's ' Befruchtung ' (1883), contains references to 814 

 papers. 



Besides the book on Orchids, my father wrote two or 

 three papers on the subject, which will be found mentioned 

 in the Appendix. The earliest of these, on the three sexual 

 forms of Catasetum, was published in 1862 ; it is an antici- 

 pation of part of the Orchid-book, and was merely published 

 in the Linnean Society's Journal, in acknowledgment of the 

 use made of a specimen in the Society's possession. The 

 possibility of apparently distinct species being merely sex- 

 ual forms of a single species, suggested a characteristic ex- 

 periment, which is alluded to in the following letter to one 

 of his earliest disciples in the study of the fertilisation of 

 flowers :] 



C. JDarwiii to J. Traherne Moggridge* 



Down, October 13 [1865]. 



My dear Sir, — I am especially obliged to you for your 

 beautiful plates and letter-press ; for no single point in natu- 

 ral history interests and perplexes me so much as the self- 

 fertilisation f of the Bee-orchis. You have already thrown 

 some light on the subject, and your present observations 

 promise to throw more. 



I formed two conjectures: first, that some insect during 

 certain seasons might cross the plants, but I have almost given 

 up this ; nevertheless, pray have a look at the flowers next 

 season. Secondly, I conjectured that the Spider and Bee- 

 orchids might be a crossing and self-fertile form of the same 

 species. Accordingly I wrote some years ago to an acquaint- 

 ance, asking him to mark some Spider-orchids, and observe 



* The late Mr. Moggridge, author of ' Harvesting Ants and Trap-door 

 Spiders,' ' Flora of Mentone,' &c. 



f He once remarked to Dr. Norman Moore that one of the things that 

 made him wish to live a few thousand years, was his desire to see the ex- 

 tinction of the Bee-orchis, — an end to which he believed its self-fertilising 

 habit was leading. 



