1S8 Prof. Schouw on the Geographic Distribution of Grasses. 
Art. XVII . — On the Geographic Distribution of the Graminece; 
with Coloured Maps. (Plates VI. and VII.) By Professor 
Schouw 
The grasses, both in respect of the economy of nature, and 
commercial intercourse, are of no small importance. In most 
countries, they form the principal part of the exterior covering 
of the earth. They materially affect the atmosphere, especially 
its quantity of moisture. They support a whole world of in- 
sects, and afford the chief nourishment of domestic animals. 
They are, on this account, of the utmost consideration in the 
breeding of cattle ; and, since the most important of the culti- 
vated plants belong to them, they constitute likewise the basis of 
agriculture. But the rearing of cattle and of corn is the main 
support of states, and determines the degree of culture, mode of 
life, and, to a certain extent also, the manner and customs of 
particular people. The geographical relations of the gramina 
must, therefore, be interesting, . not merely to the botanist, but 
to those who occupy themselves with the sciences relating to 
man, and the policy of nations. In respect of ornament, this 
class plays a very prominent part in the arrangements of nature. 
The grasses impart to the plains and hills their lovely green ; 
they border the blue waters of the lake ; and, with them, the 
spring first puts forth its vegetation. 
The Gramina are distinguished by such peculiar marks, that, 
even those who have no knowledge of botany easily recognize' 
them, the Cyperaceae alone having any resemblance to them ; j 
though, from them also, they are separated by a broad line of 
distinction not to be mistaken. 
The family is very numerous. Persoon’s Synopsis contains 
812 species, composing /^th part of all the plants therein enu- 
merated. In the system of Raemer and Schultes, there are 
1800 ; and, since this work, were it now brought to a conclu- 
sion, would probably contain 40,000 in all, it may be assumed 
that the grasses form a twenty-second part. It is more than 
probable, however, that, in future, the grasses will increase in a 
larger ratio than the other phaenerogamic plants, and that per- 
haps the just proportion will be as 1 to 20, or as 1 to 16. Greater 
* Abridged from Schouw’s Grundzlige einer Allgemeinen Pflanaen Geographie. 
