364 On the Vegetation of the Carboniferous Period, 



matter, so homogeneous that not a trace remains of the outward form 

 of that incalculable number of species and specimens of plants to 

 whose decay it owes its existence. 



Plants, whose tissues are so lax as to be convertible after death 

 into a mass of such uniform structtire as coal, evidently would not 

 retain tlieir characters well during fossiiization, under whatever fa- 

 vourable circumstances that operation may be conducted. We con- 

 sequently find that (evi specimens are available for scientific pui-- 

 poses. Of the ferns, whose remains preponderate in the carbonife- 

 rous flora, only one surface of the leaves or fronds (and that inva- 

 riably the least important, botanically speaking) is exposed to view ; 

 and their mutilation is so great, that the identification of contiguous 

 specimens is frequently impossible, much more so of those from dif- 

 ferent parts of the same or from otiier coal-fields. Were the species 

 and genera identical with those now in existence, this difficulty would 

 be lessened ; for we should then know the variations in form which 

 the individuals might be likely to assume, or at any rate, what dissi- 

 milarity between tlie isolated fragments was due to their belonging to 

 different parts of the same plant. The naturalist is thus hampered 

 in the outset by his inability to answer questions relatinp- to system- 

 atic and specific botany. And, when he turns to a general review 

 of the whole, and seeks to reclothe the globe with the vegetation to 

 whose decomposition we are indebted for coal, he labours under no 

 lighter difficulties ; the most casual inspection of such a wreck suf- 

 fices to shew that the number of species, genera, and even orders, of 

 which scarce a trace remains, must far outnumber those which are 

 recognisable. Of the latter, again, but a small per-centage is known 

 in a tolerably complete state, only the larger and better preserved 

 specimens retaining those organs and appendages which the most 

 skilful botanist requires to examine in the living vegetable, before 

 he can pronounce decidedly on its affinities. The female flowers or 

 fruit are distinguishable in very few cases, and they are so rare, that, 

 but one genus of coal-plants has thereby been referred with any cer- 

 tainty to its proper position in the natural system. They occur in 

 the form of cones (aggregations of seed- vessels j, or of isolated seed- 

 vessels. Their form alone is generally preserved, their interior hav- 

 ing been wholly destroyed, or presenting a crushed and shapeless 

 mass of disorganized tissue. The solitary nuts, again, may have 

 grown in cones or separately : they have never been found attached, 

 nor in a position relatively to any leaf, branch, or cone, that would 

 justify their having belonged with certainty to either. Of male 

 flowers, no traces remain. Leaves and scales occur abundantly, but 

 almost invariably detached, as is generally the bark of the stems or 

 trunks, so that the very outline of the vegetable is frequently lost. 

 Hence, arises the necessity, in the infancy of this science, of describ- 

 ing the different portions, perhaps of one plant, as species, and of 



