360 M. Brongniart on the Vegetation of 



Let us fiist compare, with this object, the flora of the first ve- 

 getation, that whose remains have produced the coal-beds ; those 

 great deposits of combustibles, whose utility has made them to 

 be sought out and explored in almost all countries, and whose 

 disposition and fossil vegetables are for this reason much better 

 known than those of any other epoch. The remarks which the 

 examination of this flora supply, are only as yet founded upon 

 the fossils collected in Europe and North America; but the 

 few fossils of the same epoch collected in the other parts of the 

 world, appear to agree with those of our own countries in lead- 

 ing to the same consequences. 



It had long been observed that the vegetables of this forma- 

 tion generally approach nearer to those of the warmest parts of 

 the globe, than to those of the temperate regions ; but now 

 that the fossil plants of this epoch are much better known, and 

 that their resemblance to the existing vegetables has been found- 

 ed upon a more strict examination, their relations to the plants 

 of the equatorial regions may be established on more solid 



All the plants of the class of vascular cryptogamic vegetables, 

 to which belong most of the vegetables of this epoch, acquire a 

 development proportionate to the heat of the climate in which 

 they grow ; or, rather, in cold climates, there are only found 

 small species among the plants of this class, while in the tropi- 

 cal regions there occur, together with small species, numerous 

 species of a much greater size. Thus, the Ferns of the cold or 

 temperate climates all creep on the ground, or their stem has 

 only a height of a few inches ; those of the equatorial regions 

 often attain a height of ten, fifteen, and twenty feet; the smallest 

 species of Equiseta known are those of Lapland and Canada ; 

 the largest grow in the West Indies and equinoctial America ; 

 the Lycopodia of our regions never rise higher than five or six 

 inches ; those which grow between the tropics often attain three 

 or four times that height. 



The still greater size of the Ferns, Lycopodiaceae and Equi- 

 isetaceae buried in the coal formation, therefore authorises us to 

 presume that during this period, all the circumstances calculated 

 to favour the development of these plants, had acquired their 

 highest degree. Heat and moisture are the principal, and it is 



