Bo THE ORCHID REVIEW. (Marcu, 1922. 
his first attempts to isolate the fungus from Orchid roots obtained a species 
of Fusarium. When, however, he succeeded in extracting the right fungus 
he established a criterion which enables one to settle without doubt whether 
the true fungus has been isolated, viz., that the endophyte is able to bring 
about the germination of the seed. The fungus, when living within the 
cells of the plant, shows no characters which give a clue to its systematic 
position, but when it is grown on nutrient media it shows additional stages 
of development which are characteristic. Bernard, in his experiments, 
found that the fungi, if grown in culture, gradually became inactive. 
Cultures two years old were quite unable to bring about germination. 
Burgeff, on the other hand, found that his cultures after twenty-six and 
twenty-eight months retained their power. ma 
The seeds of Orchids are very small, the embryo being generally only 
just visible to the naked eye. There is no differentiation into cotyledon, 
stem, radicle, as is almost universal in flowering plants. Seeds taken from 
the capsule under sterile conditions, and sown on ordinary compost where 
no fungus is present, rarely develop. As a rule they merely swell and turn 
green. The food reserve of Orchid seeds is most frequently oil, part of 
which becomes transformed into starch. The reserve food comes to an end 
just as the seed begins to turn green, and if no fungus infection occurs the 
seedling dies. In the culture flasks the fungus usually enters the seed 
within a few days. Entry takes place at the suspensor end of the seed. 
The suspensor is the stalk by which the seed is attached to the interior of 
the capsule, or seed-pod. The cells are invaded by degrees, the hyphe 
becoming twisted into a ball in each cell before passing on to the next. _ 
An interesting discovery is the fact that in no Orchid studied in the 
present series (Odontoglossum, Oncidium, Cattleya, Cymbidium, Vanda, 
Cypripedium, etc.), does the developing root when passing throu 
infection. Infection of the root takes place, not from the little seedling 
bulb, but from the soil or compost, and generally when the root is about a 
quarter of an inch in length, the hyphe entering by the root hairs. | 
An interesting type of mycorrhiza occurs in Gastrodia elata, a non- 
chlorophyllous Orchid widely spread throughout Japan. Unless the 
of the seeds of Gastrodia, and although it is expected that fungal infection 
1S necessary for seedling development, the exact form of fungus is 
