60 Transactions British Mycological Society. 
on humus from habitat of plant—on sterilized soil there was no 
germination. 4. Keeping cultures in the dark. 5. Moderate 
moisture. 
It is suggested that the carbon compounds of the highly con- 
centrated soil extract, acting in combination with the peptone, 
brought about germination by chemical action. 
Parallel experiments with peptone solution alone, soil extract 
alone, and with a mixture of both gave a slight germination in 
peptone solution, a stronger one in soil extract, but much the 
best is a mixture of the two. 
With regard to the question of infection of the seedling root 
from the capsule it is obvious that there is great discrepancy 
between the accounts cf Rayner and Christoph, and until the 
results of one or other worker be confirmed it is not possible 
to draw from them theoretical conclusions. That cuttings of 
Calluna can strike and come to maturity in sterilized soil 
without root infection is somewhat unexpected on account of 
Rayner’s clear description of the distribution of the fungus in 
the plant; in cultivated orchids it is quite likely that after the 
seedling stage fungal infection is not necessary. 
Concerning the germination of Pyrola rotundifolia seeds the 
account is not full enough to draw from it any theoretical con- 
clusions. The fact that the seeds can be brought to germinate 
by chemical means is not surprising: it is analogous to what 
has been found by Bernard in Cattleya. There was apparently 
no attempt made to try the effect of the root-fungus on ger- 
mination. 
EXPLANATION OF PLATES. 
PriateE II. 
Fig. 1. Transverse section of root of Habenaria just above the root tip. The 
dark masses show where digestion of the fungus is taking place. x 36. 
Fig. 2. Seed of Cymbidium, stained and mounted whole. The embryo is seen 
as an oval black patch within the network integument. x 56. 
Fig. 3. Longitudinal section of a seed of Odontoglossum. The anterior end 
shows smaller cells, the posterior end larger cells. (The intepumient has 
been ruptured in making the preparation.) x215. 
Fig. 4. Fungus from Odontoglossum (Rhizoctonia ianetnosa Bern.) at the 
beginning of sclerotium formation. x 36. 
Fig. 5. The same more highly magnified showing chains of “‘spores.”” x 215. 
Pate III. 
Fig. 6. Seed of Odontoglossum sown seven days on a culture of the fungus: 
stained and mounted whole. x56. 
Fig. 7. The same more highly magnified. x 215. 
Fig. 8. Longitudinal section of a seed of Odontoglossum nine days after sowing. 
The fungus has entered the larger cells at the suspensor end of the seed 
and formed balls of hyphae. (The integument has been broken in cutting 
the section, cf. Fig. 6.) x215. 
Fig. 9. Section of protocorm of Odontoglossum. The growing point of the 
stem can be seen at the upper end and the first and second leaves (Section 
