ON STANHOPEA. 
59 
are so inimical to constitutions used to a purer atmosphere : 
how beneficent the arrangement, then, that places here the 
most luxuriant vegetation of the world, in order to reduce these 
evil effects, in the working out of which the plants under con¬ 
sideration occupy no minor position ! — they are purifiers of no 
mean power, evidently intended for stations where no other 
form of plant could exist. Seated on the decaying stump of a 
tree, or swinging on the remains of a dead branch, whence 
otherwise would issue a stream of impure gas, to the detriment 
of the animal portion of the occupants of the country, or it may 
be, spreading themselves over the face of a craggy promontory 
whose crevices are filled with putrefying debris, they perform 
their allotted task in silence, and with positive certainty. 
Now then that we know something of their intended end, we 
may begin to admire the adaptation which suits them to such 
purposes. In the countries mentioned it is well known the 
weather is seasonal; at one period subject to the torrid influence 
of a vertical sun, which dries the atmosphere even to aridity, 
and then again deluged with almost incessant torrents of rain : 
in the latter season these plants acquire a surprising vigour; 
they form new parts, and, as it were, provide a store of suste¬ 
nance against the exhaustion consequent on the recurrence of 
the former period; and for this purpose, what form seems so 
appropriate as the pseudo-bulb or bulbous stems common to them? 
which, if examined, will be found to consist of an innumerable 
ramification of minute veins or ducts containing liquid, ali¬ 
mentary matter, covered with a thick, leathery epidermis, so as 
effectually to prevent radiation or the withdrawal of moisture, 
but by the most gradual and almost imperceptible manner. 
And then, again, the majority possess stout fleshy leaves, having 
nearly an equal absorbent and retentive power; in short, their 
roots seem to be the only ephemeral organ they have, for many 
of them we believe to be virtually deciduous, not lasting in 
actual vitality more than one season, though, from the wiry 
nature of the central portion, they are of assistanceTo retain the 
plant in its position for a much longer time. This applies to 
nearly all that have pseudo-bulbs, where, indeed, their con¬ 
tinuance is of far less moment, as the plant possesses a reservoir 
of nutriment within itself sufficient to relieve it of the necessity 
of any extraneous assistance. 
Thus, then, do these plants, which are the wonder and admir- 
