Fecundation in Orchidee and. Asclepiadea. 691 
column a glutinous disk, from which a central thread or cord of 
the same nature is continued through the style to the cavity of 
the ovarium, where it divides into three branches, and that 
each of these is again subdivided into two. The six branches 
thus formed, are closely applied to the parietes of the ovarium, 
run down one on each side of the corresponding placenta to its 
base, each giving off numerous ramuli, which spread themselves 
among the ovula, and separate them into irregular groups. 
Hence, according to this author, a communication is esta- 
blished between the anthera and the ovula, which he adds are 
impregnated through their surface, and not, as he supposes to 
be the case in other families, through their funiculus or point 
of attachment to the placenta. 
The remarkable account of the stigma here quoted, though 
coming from so distinguished and original an observer, and one 
who had particularly studied this family of plants, seems either 
to have been entirely overlooked, or in some degree discredited 
by more recent writers, none of whom, as far as I can find, have 
even alluded to it. And I confess it entirely escaped me until 
after I had made the observations which will be stated in the 
present essay, and which confirm its accuracy as to the exist- 
ence and coürse of the parietal cords, though not as to their 
nature and origin. 
In 1824 Professor Link* expresses his opinion that the rostel- 
lum of Richard is without doubt the true stigma. 
In 1829 Mr. Lindleyt, who for several years has particularly 
studied and has lately published part of a valuable systematic 
work on Orchideous Plants, states that in this family impregna- 
tion takes effect by absorption from the pollen masses through 
their gland into the stigmatic channel. 
In 1830, in his Introduction to the Natural System of Botany. 
* Philos. Bot. p. 298. t Synops. Brit. Flor. p. 256. 
the 
