654* Natural History of Nova Scotia. 



of small plants ; and frequently kills the bark of the large by 

 mechanical pressure. 



Where the soil is extremely poor, it frequently happens 

 that rocks elevated by the winter's frost and subsiding in 

 spring, and other accidents, bring a portion of naked soil to 

 the surface, upon which no common plant can live, as a seed- 

 ling of one summer's growth would be so very small, that 

 the roots would necessarily be thrown out of the ground by 

 the frost. The .Lichen ericetorum is the vegetable which 

 serves to heal these breaches in the green coating of the earth. 

 This is a white scurfy crust, which, spreading over the naked 

 soil, and shooting up little flesh-coloured tubercles that have 

 the appearance of diminutive mushrooms, strikes its roots 

 some depth into the earth, and forms a sward which prevents 

 the water from easily entering, and secures the surface from 

 being broken by the alternate frosts and thaws of winter. 

 Upon this crust caribou [reindeer] moss, and other lichens 

 spring up, soon followed by hawkweed, golden rod [Solidago], 

 kalmia, and alder. 



The ferns, with their very tough matted roots, are useful, 

 in many places, to prevent the turf from breaking. When 

 decayed leaves and lichens have slightly covered a rock 

 or mass of broken stone, on the dark shaded side of a 

 steep hill, a crop of green moss overspreads the shallow 

 soil, presently followed by a growth of polypod, whose roots 

 connect the whole so firmly, that the heaviest rains do 

 not wash it away from the sides of steep hills. We often find 

 it difficult to introduce grass into a drained swamp ; the very 

 light soil, being raised upon pillars of ice, throwing the roots 

 out of the ground ; but in these swamps, when in a state of 

 nature, the firm matted roots of the sheep polypod and the 

 horse fern are never moved. Some of the sedges, in the same 

 situation, have roots nearly as strong as packthread ; and it 

 has been found by experience, that the easiest mode of intro- 

 ducing clover and upland grasses into a drained swamp is, 

 simply, to give it a dressing with stable manure as soon as it 

 is drained, without breaking the natural turf of the swamp, 

 which always prevents the frosts from moving the surface, 

 long enough to allow the roots of the upland grasses to acquire 

 their full growth. The family of lichens comprehends the 

 crusts of various colours which overspread the rocks and stems 

 of trees, the paper-like mosses, the white caribou moss, and 

 the thread-like clusters of yellowish or black moss which 

 hang from the branches of dead trees. Although they con- 

 tain a considerable quantity of substance resembling starch, 

 and a large proportion of carbonaceous matter, they appear 



