Aucusr, 1922.] THE ORCHID REVIEW. 231 
habitable, several Orchids were noted among the successful immigrants, the 
vanguard of the family being formed of Vanda Sulingii, Bl., Cymbidium 
Finlaysonianum, Lindl., Arundina Speciosa, Bl., Spathoglottis plicata, BI., 
and a species of the genus Phaius. From this observation it would 
“seem that Orchids are perfectly capable of entering into successful — 
competition, and, under favourable conditions, are quite able to hold their 
own in a free for all combat. 
Orchids are well adapted to dispersal by the wind; consequently when 
we examine the new-born flora of Krakatau it is well to concentrate 
attention on those species of plants whose seeds were undoubtedly blown 
there from Sumatra, Java and several other countries. In 1897, that is, 
about fifteen years after the volcanic eruption, we find that seventeen 
species, or thirty-two per cent. of the flora of Krakatau, arose from seeds that 
had been wind-borne. These seventeen species represented three families ; 
eight were members of the Composite (Daisy Family), five were species of 
Graminez (Grass Family) and four were Orchids. From these figures we 
are able to draw some interesting and enlightening information. We find, 
for example, that the Orchids not only made up a large percentage of the 
immigrant flora that had reached Krakatau through the air, but they rivalled 
in successful seed dispersal two families of plants that are regarded as’ the 
most proficient in the perpetuation of their species. Their specific 
representation was much greater than that recorded for the majority of 
families that established representatives on Krakatau. With the exception 
of the Leguminosz, which were comparatively numerous in the new strand 
flora, they about equalled in number of species the more prominent families 
of flowering plants. 
At this point one begins to contemplate the part mycorrhiza played in 
the development of the Orchids on Krakatau, and to contrast what happens 
when a new area is opened to occupation in contradistinction to what takes 
place in an established, or shall we say balanced, flora. If Orchids are 
dependent for germination on ‘mycorrhiza, as we believe now that they are, 
it is reasonable to presume that the Orchid seeds which reached Krakatau 
and germinated, were previously supplied with mycorrhizal fungi. That is, 
before reaching Krakatau they had perhaps rested for a time where 
mycorrhiza were present, and then, after inoculation, they had been blown 
to their final resting place. This is not a preposterous proposal. 
Indeed it is a perfectly logical assumption. 
Although Orchids are classed among those plants which owe their 
dispersal to the wind, their seeds are not provided with special apparatus 
for suspension in the air. The embryo is surrounded by a membranous 
covering which is a structural adaptation that simply ensures buoyancy. In 
seed dispersal over great distances by the wind, reduction in weight is more 
