COMMENCEMENT OF LAND PLANTS. 45 



limited. It must, however, be observed, that there are many 

 conceivable circumstances to account for the non-preserva- 

 tion or transmission of many of the plants of this era. The 

 numerous fungi, and other lowly forms, could scarcely have 

 left clear memorials of themselves in the rocks, or in the 

 masses of coal ; and it has even been ascertained by experi- 

 ment, that some of the highest forms of vegetation perish with 

 surprising quickness in water. If we might assume, never- 

 theless, that the plants actually ascertained, form in any degree 

 a representation of the flora of this period, they would imply 

 that the early terrestrial botany of our globe was greatly less 

 varied than the present, and composed chiefly of plants of 

 comparatively simple form and structure. ( 24 J 



In the ranks of the vegetable kingdom, the lowest place is 

 taken by plants of cellular tissue, and which have no flowers, 

 (cryptogamia,) as sea-weeds, lichens, mosses, fungi, ferns. 

 Above these stand plants with vascular tissue, and bearing 

 flowers, in which again there are two great subdivisions ; 

 first, plants having one seed-lobe, (monocotyledons,) and in 

 which the new matter is added within, (endogenous the cane 

 and palm are examples ;) second, plants having two seed-lobes, 

 (dicotyledons,) and in which the new matter is added on the 

 outside under the bark, (exogenous the pine, elm, oak, and 

 all the British forest-trees are examples ;) these subdivisions 

 also ranking in the order in which they are here stated. Now 

 it is found that the predominant plants of the coal era are of 

 the cellular and cryptogamic kind, while the dicotyledons are 

 comparatively rare. There is, indeed, one exogenous family, 

 which occurs in considerable numbers, and, perhaps, figured 

 more conspicuously in the living woods than in the dead coal 

 beds namely, the conifers ; but this, again, is held as the 

 lowest family of its class. That many trees of higher families 

 now existed, seems unlikely, when we learn that such trees 

 occur in considerable numbers in subsequent formations, 

 showing that there was nothing positively to forbid their being 

 preserved in the coal measures, if they had then existed. 



The master-form or type of the era was the fern, or 

 breckan, of which about one hundred and thirty species have 



