ON THE CONSTITUENTS OF BULBS. 
81 
true species; although it is considered by some botanists as 
only a variety of altissimum. A native of Brazil; introduced in 
1837. 
Oncidium Microchilum.— A very singular species. The lip 
is very small and yellow ; the sepals and petals are yellow, beau¬ 
tifully spotted with purple. It is only a one-leaved, species, and 
easily known from all the others by its small lip. The leaves are 
very thick, and of a purplish colour. A native of Mexico ; in¬ 
troduced in 1838. 
Oncidium Erioptorum (woolly flowered) is nearly allied to 
microchilum in its habit; but I do not know what the flowers are. 
A native of Mexico ; introduced in 1840. 
There are many other species that have not yet flowered ; but 
I shall communicate them for the “ Florist,” as soon as I know 
of them. And there are new species brought into this country 
every day ; this being a genus that extends itself over nearly 
every portion of the tropical world ; and enlivens the trees with 
its beautiful flowers, and perfumes the woods with their sweet 
scent; many of the species being sweet-scented, and the Oncidium 
Lanceanum has the exquisite perfume of the violet. 
P. N. Don. 
CONSTITUENTS OF BULBS, ETC. 
Bulbous stems, for they are really not roots though commonly 
so called, are very curious bodies. They consist of a principal 
and permanent part, called the base or radical plate, which answers 
to the life-knot or collet of other plants, whence all the other 
members annually proceed. These members are, first, the real 
roots, which are either fibrous, like those of the tulip, or somewhat 
pulpy and substantial, like those of the Hyacinth ;—secondly, the 
leaves, which are of two descriptions; namely, an uncertain number 
attached to the edges of the radical plate, which are fleshy, 
abbreviated, and seldom or never expanded, forming together what 
is called the bulb ;—and thirdly, a central set, which embrace and 
rise with the flower stem, and become perfect leaves. Thus the 
roots, leaves, and flower are annual productions, which, when 
the seed is ripe, all die and disappear, except a few of the exterior 
VOL. IT. NO. IV. 
M 
