raordinary arrangement--unique among orchids, I
believe--will be discovered one day, for purpose there is, no doubt; to
judge by analogy, it may be supposed that the insect upon which _Onc.
serratum_ depends for fertilization likes to stand upon this ring while
thrusting its proboscis into the nectary. The fourth of these fine
species, _Onc. superbiens_, ranks among the grandest of flowers--knowing
its own value, it rarely consents to "oblige;" the dusky green sepals
are margined with yellow, petals white, clouded with pale purple, lip
very small, of course, purple, surmounted by a great golden crest.

Most strange and curious is _Onc. fuscatum_, of which the shape defies
description. Seen from the back, it shows a floriated cross of equal
limbs; but in front the nethermost is hidden by a spreading lip, very
large proportionately. The prevailing tint is a dun-purple, but each arm
has a broad white tip. Dun-purple, also, is the centre of the labellum,
edged with a distinct band of lighter hue, which again, towards the
margin, becomes white. These changes of tone are not gradual, but as
clear as a brush could make them. Botanists must long to dissect this
extraordinary flower, but the opportunity seldom occurs. It is
desperately puzzling to understand how nature has packed away the
component parts of its inflorescence, so as to resolve them into four
narrow arms and a labellum. But the colouring of this plant is not
always dull. In the small Botanic Garden at Florence, by Santa Maria
Maggiore, I remarked with astonishment an _Onc. fuscatum_, of which the
lip was scarlet-crimson and the other tints bright to match. That
collection is admirably grown, but orchids are still scarce in Italy.
The Society did not know what a prize it had secured by chance.

The genus Oncidium has, perhaps, more examples of a startling
combination in hues than any other--but one must speak thoughtfully and
cautiously upon such points.

I have not to deal with culture, but one hint may be given. Gardeners
who have a miscellaneous collection to look after, often set themselves
against an experiment in orchid-growing because these plants suffer
terribly from green-fly and other pests, and will not bear "smoking." To
keep them clean and healthy by washing demands labour for which they
have no time. This is a very reasonable objection. But though the smoke
of tobacco is actual ruination, no plant whatever suffers from the steam
thereof. An ingeniou