INTRODUCTION. 



That part of the material world which bears the name of the Vegetable 

 Kingdom, consists, like the Animal, of a vast multitude of species, whose 

 outer and inner forms alike oflfer a prodigious diversity of modifications of 

 one common simple plan of structure. Organic vesicles, usually extending 

 into tubes of various kinds, exclusively constitute what we call Vegetation ; 

 but this simplicity of nature is attended by very complex details of 

 arrangement, as is shown in trees, whose framework is knit together by 

 countless myriads of such vesicles and tubes, entangled with an astonishing 

 intricacy of simple arrangement. 



Any living combination whatsoever of such vesicles constitutes a plant ; 

 but as the combinations themselves are countless, so are the resulting 

 external forms ; for, although two or three words may suffice to express all 

 combinations whatsoever in their most general sense, as when the name of 

 thallus is given to the simplest expansion of vegetable matter, while all the 

 more complex forms are included under the name of axis and its appen- 

 dages, yet ingenuity is Exhausted in the attempt to distinguish by appro- 

 priate terms the manifold external forms assumed by that axis and the 

 parts which it bears. 



Hence it is that wherever the eye is directed it encounters an infinite 

 multitude of the most dissimilar forms of vegetation. Some are cast ashore 

 by the ocean in the form of leathery straps or thongs, or are collected into 

 pelagic meadows of vast extent ; others crawl over mines and illuminate 

 them with phosphorescent gleams. Rivers and tranquil waters teem with 

 green filaments, mud throws up its gelatinous scum, the human lungs, 

 ulcers, and sordes of all sorts bring forth a living brood, timber crumbles to 

 dust beneath insidious spawn, corn crops change to fetid soot, all matter in 

 decay is seen to teem with mouldy hfe ; and those filaments, that scum-bred 

 spawn and mould, alike acknowledge a vegetable origin. The bark of 

 ancient trees is carpeted with velvet, their branches are hung with a grey- 

 beard tapestry, and microscopical scales overspread their leaves ; the face of 

 rocks is stained with ancient colours, coeval with their own exposure 

 to air ; and those too are citizens of the great world of plants. Heaths 

 and moors wave with a tough and wiry herbage, meadows are clothed with an 

 emerald mantle, amidst which spring flowers of all hues and forms, bushes 

 throw abroad their many-fashioned foliage, twiners scramble over and choke 

 them, above all wave the arms of the ancient forest, and these too acknow- 

 ledge the sovereignty of Flora. Their individual forms too change at every 



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