690 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



distinct species, and further developments are confidently anticipated in a 

 very short time. 



6. True specific characters are more easy to follow in a complex 

 hybrid than varietal or even racial ones. 



7. In isolated Orchid species the pedigree of pure specific characters 

 is known to have been the same for many generations, thus being less 

 liable to reversion than mere racial or varietal characters, whose origin is 

 comparatively recent. 



The Union of Specific Characters in Intermediate 



Primary Hybrids. 



If two distinct species of Orchids of the same genus be crossed 

 together, the resulting hybrid is, as a w^hole, fairly intermediate between 

 the two parent species, e.g. Papliioijcdiliim (Cypripedium) Spiccrianum x 

 P. insigne = P. x Leeanum (Nos. 13-16). But if, according to Mendel's 

 system, the inheritance of each pair of specific characters be examined 

 separately in a number of plants, it is found that the character of each 

 species is, as a rule, inherited in difterent degrees by the hybrids. E.g. 

 the typical P. insigne has a number of well-defined spots on the upper 

 sepal of the flower, while in P. Spiccrianum these are quite absent. 



In this particular character the individual hybrids between these two 

 species (i.e. P. x Leeanum) differ considerably among themselves, even if 

 raised from the same capsule : (1) A few of them show spots equal in 

 size and number to the typical P. insigne parent. (2) A feii\ on the 

 other hand, show no spots whatever, as in the parent P. Spiccrianum. 

 (3) A few are exactly intermediate between the two parents, inasmuch as 

 they show spots reduced, in size and number, to one half. (4) The 

 great majority, however, vary in degree on either side of the true inter- 

 mediate form, up to each of the parental extremes, thus, altogether, 

 making a perfect series of intermediate forms between the two parent 

 species. 



As it is with the spots on the upper sepal, so it is with the other 

 characters of P. x Leeanum, both in colour and form. 



As it is with P. x Leeanum, so it is, as a rule, with other inter- 

 mediate 'hybrids in Orchids. Judging from my own experience, it is 

 probable that this rule might be safely extended to most intermediate 

 hybrids in both plants and animals, but for the present I will confine 

 myself to Orchids. 



This complete series of intermediate forms between the two extreme 

 parents A and a, for each pair of specific characters, is somewhat difficult 

 to classify with any precision. The word "intermediate," as generally 

 used to describe the phenomenon, is too elastic and vague for practical use. 



Thus any one form in the series, however near it might be to either 

 A or a, might be called "intermediate," while, on the other hand, if we 

 apply the term in a strict sense, only to those forms exactly midway 

 between A and a, we should probably not get more than one per cent, 

 truly intermediate, and this would be too precise, or rather too pedantic, 

 for practical use. In order to avoid this ambiguity, for the purpose of 

 this paper, I propose to define "intermediate " as follows 



In the series of forms between A and a, all those that show } A and 



