Chap. IX. CONCLUDING EEMAEKS. 279 



appearing at the distance of between eight and ten 

 miles from any place where it grew. Notwithstanding 

 the astonishing mimher of seeds produced by Orchids, 

 it is notorious that they are sparingly distributed ; for 

 instance, Kent appears to be the most favourable county 

 in England for the order, and within a mile of my 

 house nine genera, including thirteen species, grow ; 

 but of these one alone. Orchis morio, is sufficiently 

 abundant to make a conspicuous feature in the vege- 

 tation ; as is 0. maculata in a lesser degree in open 

 woodlands. Most of the other species, though not 

 deserving to be called rare, are sparingly distributed ; 

 yet, if their seeds or seedlings were not largely de- 

 stroyed, any one of them would immediately cover the 

 whole land. In the tropics the species are very much 

 more numerous; thus Fritz Muller found in South 

 Brazil more than thirteen kinds belonging to several 

 genera growing on a single Cedrela tree. Mr. Fitz- 

 gerald has collected within the radius of one mile of 

 Sydney in Australia no less than sixty-two species, of 

 which fifty-seven were terrestrial. Nevertheless the 

 number of individuals of the same species is, I believe, 

 in no country nearly so great as that of very many 

 other plants. Lindley formerly estimated that there 

 were in the world about 6000 species of Orchideas, 

 included in 433 genera.* 



The number of the individuals which comie to 

 maturity does not seem to be at all closely determined 

 by the number of seeds which each species produces ; 

 and this holds good when closely related forms are 

 compared. Thus Ophrys apifera fertilises itself and 

 every flower produces a capsule ; but the individuals 

 of this species are not so numerous in some parts of 



* ' Gardener's Cliron.' 1862, p. 192. 



