allied to the Natural Order Burmanniacee. 551 
parted petaloid perianthium. An aphyllous erect stem, with imperfectly de- 
veloped leaves, is also a character not uncommon to many terrestrial Orchideæ. 
Besides this, several instances are now recorded of the full development of three 
perfect stamens and three stigmata in orchideous plants. If these considera- 
tions alone were held in view, omitting the very material one of the stamens 
and stigmata, it would be difficult to draw a line of distinction between the 
structure of these plants and that of Orchideæ ; but the position of the sta- 
mens, and other characters, sufficiently remove them apart. 
Another analogous fact is deserving of notice: on examining the stigma of 
Dictyostega after flowering, it will be found to be crowded with bundles of 
white cottony filaments, which may be seen even with a common lens to con 
sist of pollen-tubes issuing in a body from the cells of the anthers and pene- 
trating the stigma, leaving their ends exserted, and clavately terminated by 
their respective grains, thus displaying in a very beautiful manner the sin- 
gular mode of fecundation so ably illustrated by Mr. Brown in his admirable 
paper on that subject, published in the 16th volume of the Transactions of this 
Society. The pollen also in its texture presents great resemblance to that of 
the Orchidee, its component granules cohering in like manner into a solid 
waxy mass previous to the dehiscence of the anthers. 
The position of the several parts of the flower in Dictyostega and the allied 
genera will be seen to offer very peculiar characters, to an examination of 
which I was led by the suggestions of Mr. Brown. This profound botanist 
was, I think, the first who observed* that the pistilla, when distinct, or their 
component parts, when united, are generally placed opposite to the petals in 
Dicotyledones, while he believed the cells of the trilocular ovarium, or the 
component parts of the unilocular ovarium with three parietal placentæ in 
Monocotyledones, to be situated uniformly opposite to the divisions of the outer 
series of the perianthium ; and in his learned Memoir on Cyrtandracee, lately 
published (“Plante Javanicæ, p. 110), he has given a very interesting de- 
monstration of the structure of the ovarium, and the relation which placentae 
and stigmata bear to the segments of the perianthium in several different 
families. i 
Mr. Brown considers that in Orchidee the stigmata alternate with the 
* Appendix to Denham’s Travels, p. 243.—1826. 
