$94 Proceedings of Philosophical Societies. [May, 
Peyrouse describes two others quite new, which he found in the 
same mountains, 
M. Desvaux, a botanist of Paris, has endeavoured to subdivide 
the genera of plants called cerastiwm and arenaria, now very nume- 
rous, into species. It is chiefly in the greater or less depth of the divi- 
sions of the capsule, in the greater or less dilatation of the bases of 
the stamina, and in some other analogous circumstances, that he 
thinks he has found characters sufficient to establish the division 
which he proposes. 
Another more general undertaking of the same botanist had for its 
object the large class of cruciform plants, so remarkable for the 
uniformity of its structure, and for the great utility of many of its 
species. In the division of siliculosa he has already established 12 
new genera. 
M. Kuhnt, a Prussian botanist, has undertaken a new classifica- 
tion of gramina, according to the recent labours of Messrs. de 
Beauvois and Robert Brown. He makes 12 tribes of them, each 
founded on a great many characters, such as the number of the 
styles and stamina, the disposition of the epillets, the number of 
flowers of each, the consistence and the structure of the glumes 
and vagine. 
It is easy to see that such distributions must be studied in the 
works themselves, and that the most copious analysis would only 
give an imperfect notion of them. We shall, therefore, satisfy 
ourselves with having pointed them out. 
It has long been supposed by cultivators that the neighbourhood 
of the barberry is injurious to wheat, and communicates, or at least 
favours, that species of disease called rust. Philosophers have been 
in the habit of deriding this opinion of cultivators. 
M. Yvard, our associate, at once a farmer and philosopher, has 
rather chosen to determine the fact by experiment than to embrace 
blindly the one or the other opinion ; and his observations, though 
not yet decisive, rather incline him to the opinion hitherto censi- 
dered as a prejudice. Wheat planted round a barberry bush was 
rusted, while the rest of the grain in the same enclosure remained 
untouched ; nor could M. Yvard find any other cause for this differ- 
ence than the presence of the suspected plant. 
Unfortunately, it may be objected that whole districts exist with- 
out barberry, which, however, are not exempt from this disease, 
Another troublesome disease of corn is the cockspur (ergot), or 
that long and pointed production which often comes in place of the 
grain of rye, and other species of corn. M. Decandolle, Professor 
at Montpellier, and Correspondent, has presented to the Class a 
memoir, in which he endeavours to prove that the cockspur is a 
fungus of the genus sclerotium, which assumes nearly the form of 
the grain, because at first it is moulded in the envelope of the grain, 
Its substance is analogous to that of the other sclerotiums. Its 
growth, like that of all the fungi, is favoured by humidity. Its 
