202 THE ORCHID REVIEW. [JuLy, 1922 
5. The fungus must either be beneficial, harmful, or of no effect. 
Seeds of Odontoglossum placed in culture flasks made up with ordinary 
potting material and identical in every respect, except that in one an 
‘‘Odontoglossum fungus” is present, and absent from the other, show, 
after five months, seedlings crowding one another out in the former case, 
whereas in the latter the seeds have at the most become green. It seems 
probable that originally the fungus was a true parasite on the Orchid, but 
a study of the present course of events shows that the flowering plant 
normally has the fungus well under control and might now, with a certain 
amount of truth, be regarded as parasitic on the fungus. 
Such work as that of Professor Knudson is extremely valuable in that it 
approaches the subject from a physiological standpoint. The physiological 
problems concerned, may possibly prove of the greatest importance in the 
study of immunity to disease both in animals and in plants—but to a 
mycologist an Orchid seedling without its fungus is like Hamlet without 
the Prince of Denmark. 
—_-+ 
CATTLEYA DUSSELDORFEI AQUINII. 
Are. the many hybrid Orchids exhibited by Messrs. Stuart Low & Co- 
at the recent Chelsea Show that named Cattleya Dusseldorfei Aquinit 
proved of more than ordinary interest. It is a well-known fact that in 
nearly all Cattleyas and their hybrids the sepals and petals are similarly 
coloured, indeed, we are so accustomed to see them as such that any devia- 
tion comes as a surprise. There is, however, a desire among afew hybridists 
to create flowers having the outer whorl of three sepals different in colour 
or tint to the inner whorl of two petals and the labellum. There is no doubt 
that a careful selection of parents would yield some flowers with pleasing 
contrasts in this respect. 
Cattleya Dusseldorfei is the result of crossing C. intermedia Aquinii and 
C. Mossi, and although coloured forms are in existence, this hybrid is 
generally represented in gardens by the pure-white variety obtained through 
the use of albino forms of both parents. <A few years ago Messrs. Stuart 
Low & Co. made some crosses with the intention of producing a Cattleya 
having the inner whorl of segments darker in colour than the outer whorl of 
sepals, and one of the experiments consisted of crossing C. intermedia — 
Aquinii with C. Mossiz, hoping by so doing to produce a new variety of 
C. Dusseldorfei. 
Cattleya intermedia Aquinii is figured in the Orchid Review, vol. vili-s 
p- 73, and it represents a peloriate form of this Brazilian species. It was 
originally described by M. B. Rodrigues in 1893 (Journ. des Orch., iv., p- 144)- 
In this remarkable variety the two petals bear a rose-purple area of colour 
