FIRST DIVISION OF PLANTS. 



lf)7 



ceptacles. These vary exceedingly in their form, 

 which may be round, oval, linear, convex, con- 

 cave; and in their colour, which is often briUiant: 

 they are further sessile or stipitate, with or 

 without a rim or margin. From these different 

 modifications have been formed the numerous 

 genera of this family, which were all included 

 by Linnaeus in the genus lichen. 



The lichens are in general parasitical plants, 

 living upon the bark of trees, or sometimes upon 

 the moist ground, or even upon the bare i-ocks. 

 Their substance is generally dry as if horny ; 

 and on being boiled is converted into a jelly, 

 which is nutritious, and sometimes employed as 

 food. The genera of this family are exceedingly 

 numerous, and have been variously arranged 

 according to the fancy of different authors. 



The lichens, as they are in form among the 

 simplest of plants, so tliey may be called the 

 pioneers of the vegetable kingdom. The sporules 

 of the lichen are furnished with a gummy and 

 adhesive fluid, and being scattered about by the 

 winds they fall upon bare rocks, and to these 

 attach themselves. Without soil, and simply 

 from moisture and the air, they vegetate and form 

 a small central lichen; others grow in circles 

 around, till, in process of time, the whole sur- 

 face of the bare rock becomes covered with a 

 hoary coat. These lichens periodically decaj', 

 and mouldering to the earth form with the par- 

 ticles of the abraded rocks a soil which is fitted 

 for the reception of other plants further advanced 

 In the scale of organization. Lichens also are 

 found at the extreme points of vegetation, on 

 the summits of high mountains, and near the 

 poles, where all other vegetable bodies disappear. 

 Humboldt mentions, that near the summit of 

 Chimborazo, even within the limits of the snow 

 line, the umhilicaria pustulata and the verru- 

 caria geographica are seen growing on a shelf 

 of rock: and these were the last ti-aces of organ- 

 ised nature at such a height. The most remote 

 land, the Ultima Thule of the southern hemi- 

 sphere, that has been yet explored, constitutes a 

 group of islands called New South Shetland, 

 lying off the southern extremitj' of America, 

 " Some of these islands," says the enterprising 

 Captain Weddel, "afford scarcely any vegetation, 

 save a short straggling grass which is found in 

 very small patches on spots where there happens 

 to be a little soil. This, with a moss similar to 

 what is found in Iceland, appears in the middle 

 of January, at which time the islands are par- 

 tially clear of snow." A very beautiful lichen 

 ajipears to be common there, bearing large, deep, 

 chestnut-coloured fructifications, described under 

 the name of usnea fasdata. It is the same 

 lichen probably which is noticed by Lieutenant 

 Kendal, when speaking of Deception island, 

 one of this same group. "There was nothing," 

 he says, "in the shape of vegetation, except a 



small kind of lichen, whose efforts seemed al- 

 most ineffectual to maintain its existence among 

 the scanty soil afforded by the penguin's dung." 



Tripe de Roche. An article of food extensively 

 used by the Canadian hunters in the arctic re- 

 gions of North American, is afforded by some 

 species of lichen, all belonging to a distinct tribe 

 of the liverworts, and now constituting the 

 genus UiMlicaria. It was this which, under 

 the name of tripe de roche, is described as sup- 

 porting for many days our enterprising country- 

 men Captain Sir J. Franklin and Dr Richard- 

 son, and some of their companions, when they 

 were in that country exposed to the most un- 

 paralleled hardships and sufferings from a want 

 of every other aliment; while other individuals 

 of the same party perished, incapable of sub- 

 sisting on so wretclied a diet. 



Iceland moss, (Lichen islandicus,) is used as 

 an edible substance by the Icelanders, who rarely 



79 



obtain corn bread, and whose limited stock of 

 substitutes obliges them to have recourse to every 

 species of vegetable production, which is per- 

 mitted by their inclement climate to spring 

 forth. The plant is collected by the inhabitants 

 of this northern region; and after being washed, 

 is either cut into pieces, or it is dried by the fire 

 or in the sun, then put into a bag which is well 

 beaten. It is ultimately worked into a powder 

 by being trampled on, and in this state is used 

 as food. This lichen is found growing on the 

 mountains both in the lowlands and higlJands 

 of Scotland. It consists of upright leaves nearly- 

 two inches high; soft and pliant when moist, 

 but rigid when dry. They are smooth and 

 shining, inclining to a red colour towards the 

 roots, and having the exterior surface sprinkled 

 with verj- minute black warts. The margins are 

 set witli small short stiff sporules. This lichen 

 contains a nutritious matter called lichen-starch, 

 along with a bitter principle. It is demulcent 

 and tonic. When boiled and macerated in water, 

 forms a nutritious and light jelly, which, with 



