The Natural History of British Grasses. 
469 
produce was that of a thin upland pasture. How much it has 
changed will be seen from the annexed table, which is designed 
to supply information on the following points : — 
1. The names of the grasses observed. 
2. The proportions of these observed in the meadow before 
irrigation.* 
3. The changes effected in two years. 
4. Those on the fourth year. 
Table II. — Representing the Changes of Grasses under Irrigation. 
Botanical Names. 
Alopecurus pratensis . . 
Poa pratensis 
,, trivialis 
Briza media 
Cynosurus cristatus . . 
Aira caispitosa . . 
Agrostis stolonifera . . 
Dactjlis glomerata . . 
Arena flavescens 
, ■ pubescens 
Hordeum pratense . . 
Lolium pereune 
This field has trebled in value in four years. 
This table shows us that all the better grasses have increased, 
if w e except the Poa trivialis and Hordeum pi'atense, in which 
cases there has been an increase in grasses not possessing the 
best character. Now, with respect to the first of these, it should 
be noted that though it increased rapidly up till the third year, 
it is now declining. This is explained on the supposition that 
the drainage of the irrigated part was at first imperfect, and the 
water was consequently left in a partially stagnant state ; this is 
often the case with such meadows on their first formation, but 
ultimately the water conduits become better managed, and they 
act more perfectly. And again, these changes become more 
evident where there is a gravelly subsoil : stiff clays, without a 
stratum of lighter matter, seldom succeed so well under irri- 
gation. 
So much, therefore, for the changes which take place in the 
grasses : now if we take into consideration the same set of facts, 
* The whole meadow is no^v improved, as it has been much depastured ; and 
cattle have ranged the unirrigated as well as the irrigated portion: thus irrigating 
half a meadow tends to improve the whole. 
Proportionals. 
Trivial Names. 
Before 
Irrigation. 
After 
2 years' 
Irrigation. 
After 
4 years' 
Irrigation. 
Meadow foxtail-grass . . 
1 
2 
4 
Field meadow-grass 
2 
3 
4 
Roughish meadow-grass 
1 
2 
1 
Quaking-grass 
2 
Dogstail-grass 
2 
1 
1 
Marsh bent grass . . 
1 
2 
3 
Cocksfoot-grass 
1 
2 
3 
Yellow oat grass .. 
2 
3 
3 
Meadow barley-grass . . 
1 
1 
1 
1 
2 
2 
Perennial rye-grass 
2 
4 
6 
