Y815.] Royal Institute. 149 
'M. du Petit-Thouars has made the Class acquainted with some 
interesting observations in vegetable philosophy. One among: others 
shows very well the connexion of the leaves with the woody layer 
of the same year. When a leaf falls, we see at the base of its 
pedicle a number of points, variable according to the form of the 
leaf, and the number of leaflets of which it is composed. These 
are sections of as many filaments, which are vessels, or rather 
bundles of the fibres of the leaf. If we examine the place from 
which the leaf fell, we discover the same points, and we may 
fellow the filaments into the interior of the wood; but if we make 
the same observation in the spring, upon a leaf newly developed, 
the filaments will be found to extend only to the surface of the 
wood. ‘Two or three months after a new layer of wood being 
formed envelopes them in its thickness. , 
The same botanist has made curious remarks respecting the rela 
tion of the number of stamina with that of the other parts of the 
flower, and has found that in several genera, as the polygonum, 
rheum, &c. in which this relation seems very irregular and incon- 
stant, the number of stamina is equal to the sum of the divisions of 
the calix and pistils taken together. This is a singular fact, the 
connexion of which with the general structure of the flower is not 
easily seen. 
M. Desvaux has presented a memoir on a family of plants the 
fructification of which is concealed, namely, the alg@, compre- 
hending, among others, all the sea plants called fucus. He has 
proposed to establish in them several new genera, and has made 
experiments to ascertain if the filaments by which the fuci adhere to 
the rocks, and to the bottom of the sea, be true roots. For that 
purpose, after haying detached several feet of their natural adhesions, 
e fixed them to stones by means of cords, or other artificial me- 
thods, and plunged them again into the sea. Having visited them 
some time after, he found that they had increased very sensibly. It 
was known, likewise, that some species, as the fucus natans, live 
and increase very well without being attached to any thing. 
__M. Lamouroux, Professor at Caen, has sent several memoirs to 
the Class on the same plants, which his nearness to the sea has 
enabled him to observe, and to which he gives the name of thalas- 
siophytes. After having pointed out all the divisions of which they 
are susceptible, he has considered them as furnishing food to man 
‘and the inferior animals, as useful in rural and domestic economy, 
and inthe arts. One is astonished to learn how many useful and 
agreeable purposes they are applied to by different nations, Some 
“eat them directly, or torm them into a nourishing and agreeable 
jelly : others employ them for feeding their cattle. They are all 
capable of furnishing soda, and they constitute an excellent manure, 
Some furnish sugar, others dye stuffs. Of some mats are made, 
and drinking vessels, and even musical instruments: What is 
called Corsican moss constitutes a valuable remedy, &¢, 
‘ ' (To be continued.) 
