NOTES ON SOME CURIOSITIES OF ORCHID BREEDING. 485 



fertile, very few of the latter crosses having been attempted; and 

 as it is with species so it is with hybrids. 



In the meantime perhaps the following figures will give us 

 an idea as to the relative fertility of species and hybrids in 

 the Cypripedium group. These figures are taken from the 

 records kindly placed at my disposal by Mr. Reginald Young, of 

 Sefton Park, Liverpool, and have been carefully copied by him 

 from his stud-book with his well-known care and precision. 



Taking the Paphiopediums, or East Indian Cypripediums, 

 which broadly represent the tropical species of this group in the 

 Old World (sec Mr. Rolfe, in Orchid Bevieio, iv. p. 363), I 

 find that Mr. Young has made 577 crosses among thirty distinct 

 species, and fifty-three distinct hybrids during the past five 

 years, crossing species with species, species with hybrids, 

 hybrids with species, and hybrids with hybrids, and all 

 under uniform conditions. Out of these 577 crosses Mr. Young 

 succeeded in getting 452 pods of good seed, which represents 

 78'8 per cent, fertile. An analysis of these figures shows that 

 out of 188 crosses between distinct species 179 pods of good 

 seed were obtained ; a degree of success difficult to excel even in 

 crosses between varieties of the same species, representing as it 

 does 95*2 per cent, fertile. While out of 389 crosses in which a 

 hybrid was concerned in the parentage 273 pods of good seed 

 were obtained, being 71*8 per cent, fertile, showing a decrease 

 of fertility of 23*4 per cent, in crosses between hybrids as com- 

 pared with crosses between species. This seems to point to the 

 conclusion that in this Cypripedium group while crosses between 

 distinct species are almost, if not quite, as fertile as crosses 

 between varieties of the same species, yet crosses with hybrids, 

 though fertile to a very large extent, are yet slightly less fertile 

 than crosses between species. What is the cause of this slight 

 decline in the fertility of hybrids? From Mr. Young's experi- 

 ments it seems to be due in a large measure to the loss of power 

 in the male element of the hybrid. For out of 143 hybrids 

 crossed with the pollen of pure species 128 fertile pods were 

 obtained, or 89*5 per cent., showing a very slight loss of power in 

 the female element of the hybrids of 5*7 per cent. While out of 

 118 pure species crossed with the pollen of hybrids only sixty- 

 seven pods of good seed were obtained, showing 56*7 per cent, 

 fertile. This represents a loss of power in the male element of the 



