380 On Spontaneous Generation. 



fills the intervals between the solitary trees that have escaped 

 destruction. The new vegetation which replaces the former, 

 in every part of America, is uncommonly interesting. In 

 Pennsylvania the few ancient woods, untouched by either the 

 fire or the axe, are like a park without underwood; but scarcely 

 has the fire devastated a tract, when there springs up, espe- 

 cially in the more elevated places, a beautiful Rhododendron, 

 forming an impenetrable thicket. Where no tree has escaped 

 the general conflagration, the scrub oak, {Quercus ilicifolia, 

 Wangenh.) shoots up, presenting great obstacles to the hunt- 

 er and the farmer, as it is very difficult to extirpate its roots, 

 which continually give rise to new shoots* However, the 

 consequences of the combustion of the woods are still more 

 striking in the hot parts of America. In Cuba the tree net- 

 tle, ( Urtica baccifera, L.), which bums most severely, the ugly 

 Psychotria, Piper, and other unseemly shrubs, quickly shoot 

 up, and where cultivation does not successfully struggle 

 against the spontaneous vegetation, there is formed an impe- 

 netrable thicket of hook-thorned smilax, Ipomoea, and other 

 climbers. In Chili the first plants which grow in such pla- 

 ces are the severely -burning Loasce, the stems of which are 

 either upright or stoloniferous ; then follow shrubs whose 

 seeds are prickly, and attach themselves to every object com- 

 ing in contact with them, such as Acaence, Aucinice, and ma- 

 ny others. Soon after the Colligue takes root, which is an 

 arborescent grass, as characteristic of many districts of Chili 

 as the bamboo is of the hotter countries of Asia, or the sile- 

 rias of the tropical parts of America. Numerous stalks of this 

 grass shoot from a creeping root, and in rich soil they grow 

 to the height of 12 or 18 feet. They are studded, through- 

 out their whole length, with tufts of juicy green leaves, and 

 covered with a polished yellow cuticle, which is so hard that 

 it resists the knife, and is elastic to a high degree, so that 

 they recoil with violence against him who incautiously bends 

 them. From the sea-shore up to the elevated parts of the 

 Andes, this plant finds habitats adapted to it; but near the 

 snow-line it becomes a low shrub, and presents great obsta- 

 cles to the traveller, to whom its smooth procumbent stalks 

 cause many a fall. It is as useful to the natives of Chili as 

 the bamboo is to the Hindoo ; and many parts of the houses 

 are constructed of the Colligue. It is however a great nui- 

 sance, for on grouud newly brought into cultivation, it springs 

 up among the crops in the first spring, and in autumn its 



* In the Canadas &c. when fir-woods are burnt, they are replaced by pop- 

 lars &c. 



