374 
is destitute of this ligula ; and, finally, the embryo of the two is at variance 
both in structure and position. With Asphodeleae their relationship consists 
in nothing more than the tendency to branch which is observable in part of 
that order. 
Geography. As nothing can be uninteresting which is connected with 
the habits of a tribe of such vast importance to man, I extract the following 
account of the geographical distribution of Grasses by Schouw, from Jameson’s 
Philosophical Journal for April 1825 : — 
“ Tlie family is very numerous : Persoon’s Synopsis contains 812 species, 
l-26th part of all the plants therein enumerated. In the system of Roemer 
and Schultes there are 1 800 ; and, since this work, were it brought to a con- 
clusion, would probably contain 40,000 in all, it may be assumed that the 
Grasses form a 22d part. It is more than probable, however, that in future 
the Grasses will increase in a larger ratio than the other phanerogamic plants, 
and that perhaps the just proportion will be as 1 to 20, or as 1 to 16. Greater 
still will be their proportion to vegetation in general, when the number of in- 
dividuals is taken into account ; for, in this respect, the greater number, nay, 
perhaps the whole, of the other classes are inferior. 
With regard to locality in such a large family, very little can be ad- 
vanced. Among the Grasses there are both land and water, but no marine, 
plants. They occur in every soil, in society with others, and alone ; the last 
to such a degree as entirely to occupy considerable districts. Sand appears 
to be less favourable to this class ; but even this has species nearly peculiar to 
itself. 
“ The diffusion of this family has almost no other limits than those of 
the whole vegetable kingdom. Grasses occur under the equator ; and 
Agrostis algida was one of the few plants which Phipps met with on Spitz- 
bergen. On the mountains of the south of Europe, Poa disticha and other 
Grasses ascend almost to the snow-hne ; and, on the Andes, this is also 
the case with Poa malulensis and dactyloides, Deyeuxia rigida and Festuca 
dasyantha. 
The greatest differences between tropical and extra- tropical Grasses appear 
to be the following : — 
“1, The tropical Grasses acquire a much greater height, and occasionally 
assume the appearance of trees. Some species of Bambusa are from 50 to 60 
feet high. 
“2. The leaves of the tropical Grasses are broader, and approach more in 
form to those of other families of plants. Of this the genus Paspalus affords 
many examples. 
“3. Separate sexes are more frequent in the tropical Grasses. Zea, Sor- 
ghum, Andropogon, Olyra, Anthistiria, Ischsemum, iEgilops, and many other 
genera, which only occur in the torrid zone, and are there found in perfection, 
are monoecious, or polygamous. Holcus is perhaps the only extra- tropical ge- 
nus with separate sexes. 
“ 4. The flowers are softer, more downy, and elegant. 
“5. The extra-tropical Grasses, on the contrary, far surpass the tropical 
m respect of the number of individuals. That compact grassy turf, which, 
especially in the colder parts of the temperate zones, in spring and summer, 
composes the green meadows and pastures, is almost entirely wanting in the 
torrid zone. The Grasses there do not grow crowded together, but, like other 
plants, more dispersed. Even in the southern parts of Europe, the assimila- 
tion to the warmer regions, in this respect, is by no means inconsiderable. 
Arundo donax, by its height, reminds us of the Bamboo ; Saccharum Raven- 
nae, S. Teneriffse, Imperata arundinacea, Lagurus ovatus, l^ygeum spartum. 
