68 THE ORCHID REVIEW. [MaRCH, 1914. 
With Darwin, we regard natural selection working upon variations as 
the guiding principle of evolution, and variation began before sexual 
reproduction, though it must have been much increased by the advent of 
the latter. And isolation is an absolute barrier against crossing. 
ES RAISING ODONTOGLOSSUMS FROM SEED. ee 
OME recent inquiries show that the difficulty of raising Odontoglossums 
from seed is still felt, in some cases no results being achieved when 
the conditions appear to be favourable. A perusal by a correspondent of 
the article on Fungus-Co-operation in Orchid roots sent to us by the late 
M. Noel Bernard (O.R., xiv. pp. 201-203) has elicited the following note :— 
The article on Fungus-Co-operation in Orchid roots is particularly 
interesting in connection with Odontoglossum seedlings. I believe in 
practice, apart from the fungus theory, Odontoglossum seed is now 
generally sown on pots in which an established plant or seedling is growing 
and is found to be a-successful method. Now why is this? Does it not 
point to the presence of some beneficial material in the compost due to the 
influence of the existing growing Orchid. If this is so there is a reason 
and possible explanation. It has occurred to me that if this fungus or 
matter does affect the vitality of the germinating seed, and is present in the 
compost of a growing plant, that some of the rootlets, together with a 
small piece of compost taken from the pot, cut up fine and mixed with new 
material, might prove suitable on which to grow the seed. I have to-day 
tried the experiment and await result. E. CLEMENT. » 
The Nook, Maidstone. 
_ In connection with this note it may be interesting to reproduce the 
photograph and the substance. of the note sent to us by M. Bernard. He 
remarks: The culture tubes represented in the photograph (fig. 12) are 
Ordinary glass tubes, closed by a plug of cotton-wool and covered above 
this by a cap of tinfoil, so as to render impossible the entrance of moulds or 
other micro-organisms. These tubes have been sterilised by heat before 
making the cultures. 
The left-hand tube contains seeds of an Odontoglossum which had beet 
sown antiseptically, without any other growth, on the inclined surface of the 
whitish nutritive jelly occupying the lower part of the tube, and had 
remained for a period of four months. These seeds have simply turned 
green and swollen slightly, but they have not otherwise developed, and 
they are in the photogragh only distinguishable as points on the wet surface 
of the jelly. 
