ONCIDIUM PECTORALE.
O. pectorale ; pseudobulbis ovatis compressis sulcatis diphyllis, foliis oblongis ob
tusis papyraceis scapo a basi paniculato breviorïbus, sepalis iateralibus semi-
connatis petalisque obovatis majoribus undulatis, labelli lobis Iateralibus nanis
intermedio maximo convexo undulato bilobo, cristâ ovatâ depressâ acuminatâ
margine verrucosâ tuberculisque numerosis in frusti formâ ordinatis circum-
datâ, columnæ alis truncatis.
The woods of Brazil, teeming with plants of beautiful form, rich colour, and singular structure,
have furnished this, the handsomest of the yellow Oncidiums. I am indebted for my knowledge of
it to James Wentworth Buller, Esq. of Downes near Exeter, from whom I received a specimen and
drawing in April, 1840, with the following memorandum:
“ I have ascertained that it was imported from Rio de Janeiro, and it seems to me to resemble
in habit the O. Forbesii which I received at the same time, but in the structure of the leaves it
approaches closely to O. flexuosum. The pseudo-bulbs are also furnished with leaves at their base
as well as at their point, which is the case with O. flexuosum, but I apprehend not uniformly the
case with all Oncidiums. It seems to me also that the anther, which forms as it were the termination
of the column and surmounts the stigma, (in which there is a considerable secretion of honey), is
more fully developed than I have observed it to be in the flowers of other Oncidiums; and in this
respect the flowers remind me of an effect I formerly observed in that of Peristeria elata. My
gardener accidentally bruised the anther of one of the flowers in measuring them with a carpenter’s
rule, and I observed that the flower drooped immediately, and died in the course of two days. The
other flowers are as fresh as on the day in which they first expanded, and I hope to preserve them
in full beauty for a month longer by keeping the plant in the shade.”
The arrangement of the tubercles at the base of the lip is represented in the figure at the left-
hand corner of the plate. It is difficult to describe, and may be compared for general appearance to
an old-fashioned ladies stomacher, studded with little knots; - hence the name.
The circumstance alluded to by Mr. Buller is a singular phenomenon common in the whole
Orchidaceous order. He found that when the anther was disturbed the flower quickly died. This
was not because the anther was removed, but because in removing the anther the pollen was brought
into contact with the stigma, and thus the act of fecundation was accomplished. In general, from
the absence of insects, or of those other disturbing causes to which Orchidacese are exposed in their
native places, the pollen cannot come into contact with the stigma, and so long as this is prevented
the flowers of many species will retain their freshness for weeks, as if in expectation of that event
for which they were created. But as soon as the act of fecundation is accomplished, that is to say,
from twelve to twenty-four hours after the pollen touches the stigma, the flowers collapse, the bright
colours become dim, the ovary begins to enlarge, and the beauty of the flower is gone..