ORCHID CONFERENCE. 



423 



seen, when different species of albinos are crossed, they do not always 

 breed true to albinism, but often give coloured forms, which are not 

 wanted by the Orchid breeder. 



The science of Genetics has provided a reasonable explanation of 

 these interesting results. Experiments are yet wanting to provide 

 breeders with a complete analysis of the germinal constitution of all 

 the well-known albinos, and this cannot be satisfactorily accomplished 

 until we can be quite certain as to the identification of individual albino 

 plants, and, more important still, that the albinos concerned are true 

 albinos. 



Subject to the above reservations, the following list of twenty-six 

 well-known albinos is given, with their presumed germinal constitu- 

 tions so far as ascertained: — 



Cypripediu7n callosum Sanderae .... ccRR 



C. Lawrenceanum Hyeanum ccRR 



C. X Maudiae ccRR 



C. insigne Sanderianmn ccRR 



G. X Rossetti ccRR 



C. hdlatulum album CCrr 



Cattleya Mossiae Wageneri ccRR 



C. Gashdliana alba ccRR 



C. X Hyeae ccRR 



C. X Hyeae ' Suzanne ' ccRR 



C. X Hyeae 'Jungfrau' ccRR 



C. intermedia alba ccRR 



C. labiata alba ccRR 



C. X MacJcayi Du&seldorfei ..... ccRR 



C. X MacJcayi ' Undine ' ccRR 



C. X Machayi, Westonbirt var ccRR 



G. X Brenda ccRR 



G. X Peetersiae ' Myra ' ccRr 



G. Harrisoniana alba CCrr 



G. Mendelii alba CCrr 



G. Schroederae CCrr 



G. Warneri alba Ccrr 



Dendrobium nobile virginale ccRR 



D. Wardianum album CCrr 



Odontoglossum crispum xanthotes .... ocRR 



O. Pescatorei album ccRR 



These albinos may be divided into two classes — 0 albinos and 

 R albinos. To secure all albino offspring 0 albinos must be mated 

 with 0 albinos, and E albinos with E albinos. If 0 albinos are mated 

 with E albinos, coloured forms are bound to arise. The above list may 

 serve a useful purpose as a provisional one for breeders to work upon, 

 and no doubt further results in the near future will enable us to extend 

 the analysis considerably, and also to confirm, or otherwise, the above 

 tentative germinal constitutions. 



In working with albinos Orchid breeders must be careful to 

 distinguish between true albinos and false albinos. True albinos have 

 pure white flowers and green leaves, without a trace, of purple sap- 

 colour, though yellow and green plastids are usually present in the 

 flowers. As we have seen, one or both of the colo'ur factors 0 and 

 E are absent from the germ-cells of these forms. On the other hand, 

 false albinos, like Cypripedimn ijisigne Sanderae, C. Lawrenceanum 

 Gratriocianum, Cattleya Mossiae Reinechiana, and others, have a certain 



