Orchid Mycorrhiza. J. Ramsbottom. 45 
develops the inflorescence axis in the following year: otherwise 
no flowers are produced. 
So far no results have been published as to the germination 
of the seeds of Gastrodia. One would expect that fungal in- 
fection is necessary for seedling development, but whether the 
fungus is a form like Rhizoctonia or whether there is some adap- 
tation by which Armillaria becomes operative remains to be 
seen. In either case the facts will be of the greatest theoretical 
interest. 
The course of events in Gastrodia gives some support to the 
idea that the relation of fungus and orchid is primarily one of 
parasitism on the part of the former. At times the rhizomorph 
attacks tubers and destroys them in a manner similar to that 
in which it treats potato tubers. Usually, however, the fungus 
is kept well under control and its hyphae prevented from 
spreading beyond their apportioned region—and even so being 
absorbed by the orchid cells. It is difficult to see what benefit 
the fungus can gain under these conditions. The subterranean 
strands are apparently unable to obtain nutriment from the soil, 
their function in the usual life of the fungus being that of 
“runners.” It would seem that Gastrodia has turned the attack 
of these into one of service for transmitting nutriment from the 
oak stumps to which the fungus is attached, for its own benefit: 
a colourless saprophyte unable to grow or to flower without the 
aid of one of the most destructive parasites known! 
NUMBER OF SEEDS AND DISTRIBUTION OF FUNGUS. 
When one sees the dense masses of seedlings thriving in the 
culture flasks one contemplates as to the course of events under 
natural conditions. The enormous numbers of seeds which are 
usually produced in the capsules of orchids must have struck 
the most casual observer. “‘ Not that such profusion is anything 
to boast of; for the production of an almost infinite number of 
seeds or eggs, is undoubtedly a sign of lowness of organisation. 
That a plant, not being an annual, should escape extinction, 
chiefly by the production of a vast number of seeds or seedlings, 
shows a poverty of contrivance, or a want of some fitting pro- 
tection against other dangers.’ Darwin* estimated that in 
Cephalanthera grandiflora a single capsule contained 6020 seeds 
and that, therefore, a plant with the usual four capsules would 
have 24,080 seeds. Similarly Ovchis maculata had 6200 seeds 
in a single capsule, and thus a plant having the not unusual 
number of thirty capsules would produce 186,000 seeds: “As 
this orchid is perennial, and cannot in most places be increasing, 
one seed alone of this large number yields a mature plant once 
* C, Darwin, Fertilisation of Orchids (1862). 
