218 REPORT OF THE CONFERENCE ON GENETICS. 
HYBRIDISATION AND THE SYSTEMATIC ARRANGEMENT 
OF ORCHIDS. 
By Professor Prirzer, of the University of Heidelberg. 
At the present time the natural arrangement of orchids is not yet quite 
settled. In England Bentham’s system prevails, the chief sections of 
which are founded (like that of his great predecessor, Dr. Lindley) on 
the consistency of the pollinia and their various caudicles and glands. 
On the Continent of Europe, on the contrary, most botanists hold the 
opinion that these things are adapted specially to the fertilisation of the 
Fic. 50.—Proressor PFITzER. 
flowers by insects, and therefore that they are not very suitable organs 
for establishing the principal characters of the systematic groups. In 
1887 I therefore proposed a systematic arrangement of orchids founded 
on the general morphological structure of the whole plant, and Dr. Engler 
accepts this system for his systematic works, so also does Monsieur 
Cogniaux for the Flora Brasiliensis. 
I think that hybridisation may perhaps afford a means of ascertaining 
which is the right method of classification. Of course, if an orchid is 
fertilised with another without success, it proves nothing. We know that _ 
sometimes it is quite easy to obtain a hybrid by fertilising one species (A) 
with a nearly related species (B), but that it is impossible to get fertile 
seeds from the same plants by fertilising B with A. It follows, therefore, 
