THE PRINCIPLES OF BOTANY. 
173 
herbage, and not to grow distinctive, as do the jungle grasses. 
But, however much of quality may be traced to distinct spe- 
cies, still more is due to the soil and climate ; thus, some 
forms which are valueless in the wild state, become good 
when cultivated. 
The Agrostis stolonifera, which, in our arable fields, is a 
pernicious pest, from its couch-like underground rhizomata , 
and the paucity and harshness of its herbage, is nevertheless 
a valuable grass in the irrigated meadow, as its mode of 
growth tends to keep the turf together, while it allows a free 
passage to water between and among the roots ; at the same 
time irrigation so much improves the herbage that it becomes 
almost inexhaustible in quantity and of first-rate quality. 
That cultivation, as manuring, harrowing, and rolling of 
pasture, greatly improves it there can be but little doubt, 
but somehow or other the smaller farmers cannot be induced 
to exercise care, much less to go to expense, in manuring 
grass, his theory being that, if he takes hay every second 
year, the animals in depasturing in the intermediate years 
“make sufficient manure for grass/” That animals do bring 
up and leave a quantity of manure in depasturing is quite 
true, but as this could only have been derived from the 
herbage on which they have fed, by merely feeding off a 
field, nothing is added to its manurial stock, whilst the hay- 
making constantly takes off a considerable quantity. If our 
farming friends piit their sheep on turnips by day, and then 
should fold them on their meadows at night, something may 
be transferred from the manured arable to the pasture ; but 
in reality the opposite system is usually adopted, few farmers 
thinking it advisable to rob the arable to enrich the pasture, 
while the pasture is constantly robbed in favour of the 
arable. 
As regards the value of pasture, we may then conclude 
that the best meadow will be that which consists of the best 
growth of the best kinds, but it must be borne in mind that 
not only may bad kinds be considered as weeds, but all pas- 
tures will have a variable proportion of plants other than 
grasses, some few of which may be useful in the crop, but by 
far the larger number of these can only be considered as in- 
terlopers if not positively injurious, from possessing noxious 
or even poisonous qualities. 
Now, if we look carefully into the natural history of such 
interlopers in meadows as we should deem to be weeds, we 
shall find that they might readily be classed under the fol- 
lowing heads : 
xliv. 13 
