CHAP. III. 
MARSILEACEiE. 
223 
acquire the figure of irregular polygons ; the other three- 
or four-valved thecae, of a similar appearance, containing 
three or four roundish fleshy bodies, each of which is at 
least fifty times larger than the granules contained in the 
first kind of theca, and is said by Brotero to burst with 
elasticity, — an observation which requires verification. The 
first kind of theca is found in all species of Lycopodiaceae ; 
the second is only found simultaneously in a few. The con- 
tents of both are believed to be sporules ; but no satisfactory 
explanation has yet been offered of the cause of their differ- 
ence in size, and probably also in structure. I would suggest 
that the powder-like grains are true sporules, and that the 
large ones are buds or viviparous organs, as has already been 
stated by Haller and Willdenow. A writer in the " Transac- 
tions of the Linnean Society" has figured and described the 
growth of the larger grains of Lycopodium denticulatum, 
and he considers that they exhibit the germination of a dico- 
tyledonous plant ; but, independently of any mistrust which 
may attach to the account, it is obvious enough that his own 
drawings and description represent a mode of germination 
analogous, not to that of dicotyledons, but rather to that of 
monocotyledons, but also reducible to the laws which govern 
the incipient vegetation of a bud. 
The powder-like sporules are inflammable, and have been 
supposed by Haller, Linnaeus, and others to be pollen, while 
the larger have been considered seeds ; and to a part of the 
surface of the theca the office of stigma has been attributed. 
The thecae themselves have been fancied to be male apparatus 
by Koelreuter and Gaertner. 
4. Marsileacece, 
This very curious little order consists of plants differing 
from each other so much, that, although consisting of only 
four genera, it is necessary to subdivide it into two distinct 
tribes. As I have never had an opportunity of examining 
these plants in a fresh state, I beg to cite the observations of 
Adolphe Brongniart, who appears to have given them an 
especial attention. 
In Marsileaceae, properly so called, says this botanist, 
