436 PALEOBOTANY. 



In the Devonian period — as we now know, from the re- 

 searches of Dr Dawson of Montreal in particular — plants are 

 very abundant, and belong to varied types. The great group 

 of the Gymnospermous Exogens is here represented by 

 remains of various Conifers {Dadoxylon, Ormoxylon, and Pro- 

 totaxites). The Ferns are represented by numerous species, 

 in many cases not far removed from types now in existence ; 

 and it is interesting to notice that Tree-ferns (Fsaronius and 

 Caulopteris) are not wanting amongst these. The Zyco- 

 'podiaxece or Club-mosses are represented in the Devonian 

 series by numerous remarkable types, such as Lcpidodcndron, 

 Lepidaphloios, Cordaitcs, and Lycopodites. The Sigillarioid 

 plants, regarded by different authorities as being Coniferous, 

 or Lycopodiaceous, or as being intermediate between the 

 Acrogens and Gymnosperms — are represented by species of 

 Sigillaria itself, with its Stigiiuiria roots. The Horse-tails 

 or Eqiijisctacem are represented by species of the remarkable 

 genus Calamites. The genus Antholitlies, commonly supposed 

 to be the spike of fructification of some phanerogamic plant, 

 and now known to bear the probably Gymnospermous fruit — 

 Cardiocarpon — is represented by two species in the Devonian 

 rocks. Lastly, the Devonian formation of the State of New 

 York has yielded the remains of a supposed Angiospermous 

 Exogen, which has been described by Dr Dawson under the 

 name of Syringoxylon mirabilc. 



We thus see, even from such an imperfect summary as the 

 above, that we must abandon tlie old view that nothing like 

 a general and varied flora existed in times anterior to the 

 Coal-measures. Leaving the imperfectly known floras of the 

 Lower and Upper Silurian, and of the still older Cambrian, 

 on one side, we see that at a point of Paheozoic time as 

 early as that represented by the Devonian formation, the 

 earth exhibited a far from scanty vegetation, composed of 

 true land-plants, and embracing representatives of almost all 

 the great groups of plants wliich at present grow upon its 

 surface. Thus, we find in the Devonian rocks representa- 

 tives of the groups of the Horse-tails, Club-mosses, Ferns, 

 and Gymnospermous and Angiospermous Exogens. We 

 have, however, no certain representative of the great group 



