January, 1y13.-] THE ORCHID REVIEW. 15 
should go in for allied kinds. It was useless to grow so many kinds under 
the same treatment. His advice was to take up smaller subjects and do 
them well. 
The last paper was Albinism in Orchids, by Mr. R. G. Thwaites. The 
lecturer said he was dealing with a controversial subject, and he made his 
remarks in no dogmatic spirit, but he had obtained many coloured forms 
from white parents when he expected to obtain albinos, and he found it 
most difficult to follow the theories of various writers. Some whites seem 
to possess a colour factor not discernible to the eye, and he found it 
difficult if not impossible to differentiate between the pure white and the 
apparent white except by experience of the progeny. He thought that, as 
in the case of the spectrum, white Orchids were, in some wonderful way, 
built up by colour, for he had produced white by crossing purple with 
yellow flowers. Dendrobium nobile virginale if selfed invariably produced 
white flowers, and the same could be said of Cattleya labiata alba. Most 
albino Orchids were varieties of coloured forms, and only when a white 
variety was constant for years was it a true albino. When these were 
crossed he believed they never gave coloured forms. In conclusion he 
appealed for the discontinuance of the practice of using the term alba for 
varieties unless one could be assured of the correctness of the term. 
Mr. Rolfe, in opening the discussion, said it would be interesting and 
valuable if something reliable could be ascertained about the subject. 
Albinism was a quality—a very beautiful quality—and no doubt it arose 
from the absence of colour, but there was the difficulty that some albinos 
reproduced themselves true when selfed and yet reverted to coloured forms 
when crossed. Both Cattleya Warneri alba and C. Gaskelliana alba were 
true albinos, as far as could be ascertained by examining the flowers, but 
when crossed together some of the resulting seedlings were pure white and 
others light rose, showing that a latent colour factor had been revived. Inthe 
case of C. intermedia alba x Mossiz Wageneri, however, the whole batch 
(C. Dusseldorfii Undine) was white. Cypripedium insigne Sanderz, when 
crossed with C. callosum Sandere or C. Lawrenceanum Hyeanum, gave 
tise to coloured hybrids, yet all three came true when selfed. C. insigne 
Sanderz, however, though one of the best yellows, was not a true albino, 
for it showed minute brown spots on the dorsal sepal, and the effect of 
crossing was to stimulate their development in the hybrids, the effect being 
much the same as if ordinary coloured forms of C. insigne were used. The 
effect of crossing was to revive a latent factor, and of course when plants 
were selfed no new and disturbing element was introduced. But even 
when plants were selfed the offspring were not always uniform. Messrs. 
Veitch had raised a batch of C. insigne Sandere by self-pollination, and, 
