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JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



colour, and it would therefore seem advisable to use with the 

 Sophroiiitis the albino form — e.g., Cattleya Mossiae Wageneri and 

 C. Gaskelliana alba. If the (0) albinos of G. Warneri and G. 

 Sohroederae are used, care must be taken not to put them in the same 

 experiment in which the (E) albinos of G. Mossiae and G. Gaskelliana 

 are used, otherwise the sap-colour will appear. 



In place of Sofhronitis grandiflora, the species Laelia harpophylla 

 or L. cimiahariiia might be used, but the result would be a lighter and 

 more orange shade of scarlet. 



In the making of a self-yellow Cattleya, the species Laelia Gowanii 

 or L. flava would appear to be the best to use. G. Dowiana aurea and 

 L. xanthina, being bi-colors, would be unsuitable for breeding selfs. 

 It is rather curious that, while the yellow colour of G. Dowiana aurea 

 is completely recessive to the rose-purple colour of the Cattleyas, 

 the yellow colours of L. Gowanii, L. flava, and L. xanthina are domi- 

 nant, though in most cases the dominance is incomplete. The 



results suggest that the colour of the front lobe of the lip may be 

 inherited independently of the rest of the flower. The bi-colors G. 

 Dowiana and L. xanthina give purple or crimson lips when mated 

 with albinos, while L. Gowanii and L. flava apparently do not; but 

 L. flava when mated with the coloured forms of certain species gives 

 a crimson or purple lip, while with other species it gives a self-yellow 

 flower. L. Gowanii so far appears to give all yellow selfs with both 

 coloured and albino forms. 



In the making of a self -yellow Gattleya, all these details will have 

 to be carefully considered by the breeder in choosing his matings. It 

 may be interesting to anticipate that a rather curious point will arise 

 in the making of these scarlet and yellow Cattleyas. Technically, 

 according to the present rules, the scarlet Cattleyas bred in the way 

 suggested would belong to the genus x Sophrocattleya, while the yellow 

 Cattleyas would be classed as x Laelio cattleya. But, as the writer 

 pointed out in 1904, the generic characters which separate Gattleya 

 from Laelia — i.e. four pollen-masses and eight pollen-masses respec- 

 tively — themselves behave as Mendelian characters, and segregate in 

 "F2 in the same way that specific and varietal characters do. Conse- 

 quently some of the scarlet and yellow Cattleyas raised in these 

 experiments will have four pollen-masses only, and in that sense would 

 be indistinguishable from the systematist's true Gattleya. Being 

 homozygous, they would also breed true to that character. In view 

 of this, it hardly seems logical. to call them x Laelio cattleya; and if the 

 Orchid breeder, for other reasons of his own, chooses to call these forms 

 Cattleyas, in the circumstances it will be a rather difficult matter to 

 deny him. 



Economics and Eugenics. 



The application of the principles of Genetics to Orchid breeding 

 brings out an economic point of considerable importance, the apprecia- 



* Hurst, C. C, " Mendel's Discoveries in Heredity," Trans. Leic. Lit. and Phil 

 Soc. vo]. viii. (1904), p. 129. (See also Orch. Rev. vol. xi. (1903), p. 233.) 



