B O T A N Y. 



71 



V prosecute such researches, without the embarrass- 

 -, hich frequently restrain the exertions of the 

 *~V~* most yralmis of Nature's pupils. 



We have ; ;>Ku-d our view of the structure 



and functions of living vegetables, of both of which 

 v..- have endeavoured to exhibit as perspicuous and 

 concise a view, as the state of the science and our li- 

 mits would permit : We now arrive at that period of 

 the vegetable when its existence ceases. Every plant, 

 t.v.li. after performing its destined functions, dies, and be- 

 comes subject to all the laws of chemical^ decompo- 

 sition, which has, in a former Section, been selected 

 as a distinctive character of inanimate matter j but, 

 previous to its dissolution, if we may so express it, it 



>is subject to many diseases, which are generally fully 

 detailed in large works treating professedly of the ve- 

 getable economy : It is sufficient to mention the ex- 

 istence of such circumstances. 



SECT. VIII. Physical 'Distribution. 



lysical ALTHOUGH not strictly belonging to individual 



trilm- physiology, we cannot refrain from giving, in this 

 place, a few observations on a part of what has teen 

 termed The History r,f Plants, because it points out 

 tome of the most interesting general relations of the 

 different kingdoms of nature, and because the few 

 facts that have been developed are likely to initiate us 

 more completely into the habits of plants, than any 

 other species of inquiry that has hitherto been pur- 

 sued. The floras of different countries which have 

 been made by botanists, effect, on a limited scale, this 

 great object, by pointing out the geographical distri- 

 bution of plants ; but, it is evident, that little can be 

 done by all the knowledge thus acquired beyond the 

 individual facts. By entering upon a wide, though 

 more difficult field, much may be effected j and the 

 industrious philosopher, who engages in it, will reap 

 a rich harvest. The relative physical distribution of 

 plants opens the way to new discoveries, and, fortu- 

 nately,'the examination has been lately prosecuted by 

 Humboldt, Von Buch,and Wahlenberg, with zeal and 

 success. It is shewn, by the floras of different coun- 

 tries, that the actual heat of every climate influences 

 its vegetable productions, in form, size, colour, and 

 numbers, in a very considerable degree. " In Spitz- 

 bcrgen," says Professor Willdenow, " there are 30 

 plants ; in Lapland 534 ; in Iceland 553 ; in Sweden 

 1299; in the Marquisate of Brandenburg 2000; in 

 Piedmont 2800 ; on the coast of Coromandel nearly 

 4000; as many in the island of Jamaica; in Mada- 

 gascar above 5000." It has been also observed, 

 that the plants of cold regions are low, with small 

 leaves, and flowers proportionally large. The pro- 

 ductions of the warmer regions are distinguished by 

 their greater size, and splendour of their flowers. 

 Much variety is exhibited in similar geographical si- 

 tuations, from the accidental interposition of moun- 

 tains, plains, lakes, &c. Every soil has some pecu- 

 liarity, which must, of necessity, influence the plants 

 which grow in it. And every one of the produc- 

 tions of each individual situation, from the majestic 

 Adantoniu down to the most humble moss, is subser- 

 vient to some great and important end. Sometimes 



they promote vegetation, sometimes they perform V>getabl< 

 more extensive operations in the great scheme of Na- ' 

 ture ; and, however imperfectly we see through the 

 designs of Providence, the general benefit of the 

 whole attained by the reciprocal efforts of every in- 

 dividual, cannot fail to attract at once our admira- 

 tion and our gratitude. All, or at least many, of the 

 objects attained by the physical distribution of the 

 vegetable kingdom, is yet concealed from our view ; 

 but a careful investigation would furnish us with 

 facts, on winch we may hereafter found more com- 

 plete general deductions than any that have hitherto 

 been framed. A few such facts have been already 

 determined with regard to land plants, and we have 

 hinted at them generally. There are, in addition, a 

 few observations on the history of water plants, 

 which are worthy of record. This class of plants is 

 more generally dispersed than any other. The more 

 uniform temperature of the fluid in which they vege- 

 tate, renders their distribution more generally the 

 same. Thus the Lcmnn minor is found not only in 

 every part of Europe and of North America, but 

 also in the sultry regions of Asia ; and many other 

 examples might be adduced, of an equally character- 

 istic nature. The above observation applies not only 

 to fresh water plants, but also to those that grow at 

 the bottom of the sea, where the cause which acts in 

 the former instance possesses a still greater influence. 

 If the sketch just given be correct, it follows as a 

 natural consequence, that wherever soil, temperature, 

 and other circumstances, are similar, there is a strong 

 probability of the existence of the same plants ; and 

 that wherever these circumstances vary, that the ve- 

 getable productions will also be different. It is this 

 fact that renders the physical distribution of plants 

 an object of curious attention. We find, from all the 

 observations with which we are acquainted, that a cer- 

 tain class of plants seem to follow the snow line ;* and 

 other relations have been noticed. Many facts have 

 been determined with regard to individual distribution, 

 but few general conclusions have been obtained, except 

 by the gentlemen whose names we have mentioned.. 

 As a specimen of the observation which we consider 

 likely to be advantageous, we extractDr Wahlenberg's 

 account of the Lapland distribution, from Dr Smith's 

 translation of Linnaeus' Lapland Tour ; and with it 

 we shall conclude our view of Vegetable Physiology, 

 and of those subjects which appear to have an imme- 

 diate reference to that science. 



"1. On approaching the Lapland Alps (Fjally, 

 \ve first arrive at the line where the Spruce fir, Pinus 

 a/lies, ceases to grow. This tree had previously as- 

 sumed an unusual appearance; that of a tall slender 

 pole, covered from the ground with short, drooping, 

 dark branches ; a gloomy object in tliese desolate fo- 

 rests ! The llubus drclicns had already, before we 

 arrived at this point, ceased to bring its fruit to ma- 

 turity. With the spruce we lose the Rosa cinnamo- 

 mca, Convallaria bifolia, Sec. ; and the borders of the 

 lakes are stripped of their ornaments of Arnndo phrag- 

 miiex, Li/simacliitt tln/rsi/lora, Cia/iitm borealc, and 

 Carcx glubnlaris. Here is the true station of Tiissi- 

 lago tiii'ea, (Wiild, Up.. PI. v. 3. 1970.) The last 

 beaver-houses are seen in the rivulets, and no pike 



The snow-line, in these regions, has been found on an average to be about 4200 feel. 



