1893. EVOLUTION WN THE GUIANA FOREST. 41 
present time (September) the mango has been flowering for two months, 
and trees may be seen in different stages from unopened flower buds to 
half-grown fruit. The fruit will ripen from December to February, 
when the great mango-season will be over, and only a fruit here and 
there be obtainable until June and July, when a second crop matures. 
The result of the two cycles and the difference in flowering and 
fruiting of individual trees is that most tropical fruits are obtainable 
more or less for six to eight months of the year, being, however, far 
more plentiful during the few weeks of each season when the 
majority ripen. 
It is hardly necessary to bring evidence in favour of individuality 
among cultivated plants. Every gardener and florist knows that it is 
impossible to predict absolute uniformity in the offspring of a single 
plant, even when the greatest care is taken to prevent crossing. 
Everything goes to prove that the same individuality can be found, 
more or less, throughout the plant world, but it is especially recog- 
nisable in tropical plants. The analyst notes differences in the 
amount of active principle in samples of drugs, the tanner in barks, 
while the wood-cutter accounts for one log being more durable than 
another by false notions of the moon’s influence. 
Leaving the trees of the forest, which are so difficult to investi- 
gate particularly, and coming to the epiphytes which grow upon 
them, we find specialisation carried to extremes in the great orchid 
family. The collector, the dealer, and the grower will all admit 
individuality here. The varieties are so numerous as to be almost 
impossible to define. Not only are there differences between plants 
of the same species from several localities, but even among those 
collected within a small area, Any grower who knows his plants will 
recognise one from another, and be continually on the look-out when 
each flowers for the first time. On account of these differences, 
orchid collecting is particularly fascinating. A dozen plants of one 
species are bought at auction, and, until they flower, no one can tell 
how they will turn out. We often hear of unique specimens, but the 
fact of the matter is every one is unique. 
In the case of the orchids, there can be no suspicion of man’s 
interference. Artificial selection may have been concerned in the 
development of other families, but not of this. The wonderful varia- 
tions in the leaves of crotons and flowers of the hibiscus family may, 
perhaps, be due, to some extent, to their appreciation by the Poly- 
nesians, but the Indians of Guiana wear no garlands, nor do they 
cultivate a single flower for ornament. It is not only among the more 
showy genera, such as Cattleya and Odontoglossum, that individuality is 
conspicuous, but brassias, gongoras, and even some of the more 
insignificant families, are equally variable. 
It is only in our gardens that we can observe the many variations 
of large trees, and here we have, unfortunately, but few species from 
the forest. By studying the vegetation on every trip to the bush, we 
