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226 Pawson: Water-Plants as\ Land-Winners. 
several ways in which these plants tend to diminish the water- 
space and to increase the dry land. By their own decay they 
form vast masses of vegetable soil in shallow waters and on 
water margins ; by occupying running streams they moderate 
the flow of the current and give it time to deposit its silt; by 
their creeping rhizomes and spreading roots they fix the bed of 
a stream and prevent it from being scoured and deepened by 
floods, and again in times of flood they serve as a sieve or 
strainer, arresting all floating and much suspended solid matter. 
In England we have not to do with mangrove swamps and 
the jungle shrubs of tropical deltas, and yet even on the sea-_ 
shore there are plants which are helping the land to fight the 
waves. Many small herbs flourish on the brackish mud-flats 
where the shore is gaining on the sea, and by fixing the soil 
with their roots and by retaining the mud which every high tide 
throws over them they aid in securing the conquest. These are 
chiefly Chenopodiacee, with some Grasses and Rushes, and their 
work may be well seen on the northern shores of Morecambe 
ay. Where the wind blows the sea-sand into hillocks and dunes 
it is the Marram-grass which renders them firm and stationary, so 
that in many places a penalty is enforced on those who disturb it. 
But it is our freshwater plants that we must chiefly consider, 
and these are nearly all herbs and for the most part Grasses and 
Sedges and their allies. margin of the water seems to 
nourish vegetation better than the land; it is noteworthy that — 
the various species which choose shallow water or the edge of 
the water for their home are nearly all the most robust of their 
family. The common Reed is by far the largest of our grasses, 
taking bulk as well as height into consideration, and next to 
it, and at a long interval from those ofthe land, come other 
water-grasses, as Digraphts and Glyceria aquatica. The same 
rule holds good of the Sedges and other Cyferace@. The Club- 
rushes and Bulrushes are large plants, so are the Water-flag and 
the Bur-reeds ; the Hairy Willowherb, the Loosestrifes (purple 
and yellow), the Hemp Agrimony, the Flowering Rush, the 
Great Spearwort and the Arrow-Head, the Fen Ragworts (now, 
alas, all but extinct !), and the Marsh Umbellifers, Crcuéa, 
Stum, Genanthe, and Peucedanum are among the stoutest of 
our native herbs. 
t no doubt, the necessity of preserving shondetees 
from Hanis overwhelmed that has made these water-plants So 
vigorous, but the consequence is that their annual rise and _ 
_ decay soon accumulates an enormous amount of vegetable ‘ 
Naturalist, 
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