190 TRE ASSOCIATIONS OF FLOWERS 
diminishes the size of the knobs, which when brought into 
England are not larger than a walnut. This root is pul- 
verised and sold as salep. 
I'he wild orchises of Great Britain all grow in the 
ground; but in the tropics orchis plants grov/ on trees, 
forming some of the most elegant floral appendages of the 
boughs of the damp forests of South America. Though 
they grow from the branches and stems of other plants, 
they are not strictly parasitic, as they do not weaken the 
tree on which they hang by nourishing themselves upon its 
juices; but, deriving their sustenance either from the soil 
lying about their bases or among their branches, or by 
insinuating their fibrous roots into the bark, they acquire 
support, and are fed by the damp atmosphere about them, 
like the mosses of our own land. 
So immense is the number of plants which there hang 
among the trees, and so closely are the trees placed to- 
gether, “ that, ’ ’ says Baron Humboldt, “ were it not for 
intervening rivers, the monkeys, almost the soje inhabit- 
ants of these regions, might pass along the tops of the 
trees for several hundred miles together without touching 
the earth.” 
The orchises of the tropics, although in their general 
appearance like those of our own land, are not in any of 
their species exactly like them. Those which resemble 
insects are much more numerous than ours. The beauti- 
ful butterfly plant of Trinidad has large red and yellow 
blossoms which, as they wave about in the air, resemble 
some of our gaudiest butterflies; and one tropical species 
is so like one of those elegant lizards which are found in 
hot countries, that even those who have often seen it are 
again and again deceived by it. 
Our hothouses often display the beautiful tribe of epi- 
dendrums, hanging merely from, a tuft of moss, and receiv- 
ing their aliment from the w^arm, moist air ; and nature 
does not offer to the florist a more beautiful production 
than the air-orchis, which, if hung up in a roorn, will con- 
tinue to unfold, for several successive wrecks, its fragrant 
and delicate flowers. It is a native of the East, and is 
peculiarly beautiful in China; but it does not attain per- 
fection in this country. 
The orchideous plants (Orchidege) are very similar in 
