FERTILIZATION OF CATTLEYA LABIATA. 397 
is well represented in Darwin’s ‘ Fertilization of Orchids’ at 
p. 161, where also some structural details are given. In the 
series of drawings made for illustra- Fig. 2. 
tion, fig. 1 represents the front view of ` 
the column and ovary of Cattleya labi- 
ata, var. Mossie, two thirds natural 
size, a few days after the expansion of 
the flower. From the apex or top of 
the pollinary apparatus to the base of 
the ovary it is about 3 inches long; 
although shown upright in the figure, 
it slightly arches forward from below 
the stigma to the apex, the part so bent 
is thence parallel with the labellum, 
which is, in fact, appressed to it, and 
enfolds it with its side lobes, a circum- 
stance that immensely facilitates the 
pollination of the stigma by insect 
agency. The stigmatic cavity is sepa- 
rated from the anther by a tongue- 
shaped rostellum; the stigmatic sur- 
face is coated with a thick layer of 
transparent viscid matter which holds 
the pollinia when applied to it with 
extraordinary tenacity. The pollinia 
are four in number, each pollinium, or 
pollen-mass as we are more accustomed 
to call it, is a waxy flattened disk, 
neither strictly oval nor strictly circular, but something between 
the two, or nearly the shape of an artist’s palette, and is furnished 
With a semitransparent ribbon-like caudicle, which is also covered 
with numerous pollen-grains. The ovary is cylindric, and is 
traversed longitudinally by three equidistant sunk lines. Fig. 2 
represents a longitudinal section of the column and ovary, one 
fourth larger than natural size, in which the positions of the 
anther, rostellum, and stigma are shown by the letters P, A, 
and § respectively ; there is a duct or canal leading from the 
stigma to the ovary, down which the pollen-tubes pass. This 
canal in transverse section has the form of a W-shaped curve 
ext ending through the central part of the column where 1t 18 
thickest, as shown in fig. 4; it is filled throughout with con- 
