AUGUST, 1922.] THE ORCHID REVIEW’. 229 
OBSERVATIONS ON THE CAPACITY OF ORCHIDS TO 
SURVIVE IN THE STRUGGLE FOR EXISTENCE. 
By OAKES AMES, F.L.S., Bussky INSTITUTION, HARVARD UNIVERSITY. 
l we visualize the sequence of the flowering plants from an evolutionary 
point of view as a genealogical tree, the branches of which represent 
the taxonomic concepts of botanical classification, we see one branch given 
over to those families which are grouped together as the monocotyledons. 
At the tip of this branch the family of the Orchids 1s placed as the most 
highly organized group, set apart, among other characters, by complexity of 
floral structure. In brief, among ‘the grasses, palms, lilies and irises, to 
mention only four of the forty-five families that constitute the mono- 
cotyledons, the Orchids hold the loftiest position. 
Although the Orchid Family is admitted to be one of the most complex 
concepts of the vegetable kingdom, we sometimes read or hear statements 
which lead us to believe that it is a decadent group. To those who derive 
pleasure from an intimate association with Orchids, either in greenhouses 
or in the field, and to those who unconsciously have come to regard these 
plants as highly organized products of evolution, it is indeed surprising to 
learn that anybody should suggest seriously that they are for the most part 
moribund species. 
The outstanding characteristic of the Orchids that is regarded as a sign 
of decadence is lavish yield of seed coupled with sparse distribution. 
This seems to indicate a waning capacity to compete with more vigorous 
plants. Aside from this characteristic there are bits of accepted evidence 
which lead to the belief that Orchids have become so specialized that they 
are slow to adjust themselves to changes in their environment. They seem 
to be so delicately balanced in their relation to other organisms that they 
occupy a precarious position in the realm of living things. They are 
supposed to be unable to hold their own in keen biological competition and 
are consequently thought to be in danger of becoming extinct. They have 
been called end products. They have been mentioned by a recent writer as 
occupying the same position in the floral world that flamboyant motifs hold 
in the development of a national art. Just as flamboyancy in art has 
marked the passing of a civilization, so in the animal and vegetable 
kingdoms an excessive development of iridescence and fantastic excrescences 
indicates types of organic development that precede decadence and 
extinction. 
Another peculiarity of the Orchids that inclines us to believe that 
decadence is not a purely hypothetical condition is their dependence on 
mycorrhiza. It has been claimed that the Orchid seed, under natural 
conditions, is incapable of passing beyond the embryonic stage unless 
