230 THE ORCHID. REVIEW. [AuGUST, 1922. 
invaded by the hyphe of a mycorrhizal fungus. When the seeds are 
disseminated they lie dormant until association with the necessary fungus 
is established. Whether or not there are numerous exceptions to this 
_ peculiarity has little to do with the case from the point of view taken by 
those authors who would have us believe that the Orchids are on the 
decline as a biological group. The relationship between the fungus and 
the Orchid has been termed luxury-symbiosis ; an association that has been 
regarded as harmful. 
When we attempt to analyse the evidence brought forward to prove 
that the Orchids are a decadent group; a group that has become so 
specialized that its members are.unable to carry on a successful struggle for 
existence in the ordeal of biological rivalry, we find our knowledge sadly 
incomplete. Very few opportunities have been given us to ascertain just 
how moribund the Orchids are. That is, we do not surely know that 
extinction is prevalent among them, nor are we aware from numerous 
observations how readily Orchids spread to new land areas when equal 
opportunities in competitive distribution are offered. We are unable to 
postulate, from repeated investigations made in different parts of the globe, 
what position the Orchids really hold among the families of plants that are 
characterized by the capacity to occupy new land and become an established 
element in the formation of a flora. We simply find it possible, in the 
majority of cases, to draw conclusions from observations of what is 
practically a static condition. Because many species of Orchids are rare, 
notwithstanding their prodigality in seed yield, we infer that they have 
lost the ability to win out in a conspicuous degree when subjected to com- 
petition. Rarity is evidence of a losing contest ; at least it is a condition 
from which to argue that inability to spread is bound up with tendencies 
toward extinction. 
When in August, 1883, one of the most stupendous volcanic outbursts of 
historic times devasted the small group of islands situated in the middle of 
the Sunda Strait between Java and Sumatra, keen interest was taken by 
botanists in the re-vegetation of the sterilized land masses of Krakatau, 
Verlaten and Lang Islands. These islands, immediately after the distur- 
bance which covered the whole neighbourhood for a distance of twenty-two 
miles with glowing stones and hot ashes, were without a vestige of life. 
Their vegetation had been completely exterminated. Here an exceptional 
opportunity was offered for the study of the formation of a new flora under 
conditions that represented equal chances for invasion of the islands and 
possession of sterilized ground. 
As plants began to find congenial conditions for growth on Krakatau, 
and as the formation of a new flora was well under way, Orchids made their 
appearance. Fifteen years, or thereabouts, after Krakatau was again. 
