461 THE FLORA OF WATER-MEADOWS. 
Concerning the cryptogamic plants, it need only be said that, 
excepting a few species of Mosses in each case, Ophioglossum vul- 
gatum, L., occurs sparsely on the dry meadows at Rothamsted, 
and Equisetum palustre, L., on the water-meadows. 
Whatever peculiarities exist in the herbage of the water-mea- 
dows which I have had under observation are probably largely 
attributable to the periodical influence of running-water. The 
flooding of the meadows at intervals during the winter enables 
the herbage to enjoy a higher temperature than is the case upon 
non-irrigated grass-lands, and this promotes early spring growth. 
The meadows are, moreover, rendered independent of the effects 
of deficient rainfall, so that even in seasons of the severest drought 
the removal of the hay-crop brings to view a sward which is bright, 
fresh, and verdant. Thus, whether the season be wet, or dry, or 
of average rainfall, it is much the same to the water-meadows. 
Any seasonal influences to which they may be susceptible must 
therefore be sought rather in the general conditions of atmo- 
spheric temperature, and in the duration of sunshine in the growing 
season, than in the amount and distribution of the rainfall. 
Of the origin and history of these water-meadows little or 
nothing is known. Marshall, writing in 1798, asks, “ When 
and in what manner, was so great and spirited a public work 
executed?” I can find no record of their having been made the 
subject of any special botanical investigation, but the following 
quotation from the author just mentioned conveys some idea as 
to their condition a century ago * :— 
- “The herbage of the watered beds is various in species; 88 
ray grass, the meadow poe, the marsh and other bent grasses, 
and the meadow fescues ; the loliacea and the pratensis, here putting 
on very different appearances. On the sides of the trenches, and 
ditches, the flote fescue, reed canary grass (Phalaris arundinacea), 
and the water poe (Poa aquatica) are common; also the meadow 
rue (Thalictrum flavum), and the water dock. One meadow I 
observed was almost shaded over with the common dock ; which 
appears to be a prevailing weed of the well-formed grounds; and 
almost the only one." 
* The Rural Economy of the Southern Counties ; comprizing Kent, Surrey, 
Sussex, the Isle of Wight; the Chalk Hills of Wiltshire, Hampshire, &c. By 
Mr. Marshall. 1798, vol. ii. p. 335. 
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