THE CARBONITKROCS FLORA. 



125 



and complicated stems belonged to higher and nobler 

 types of mare's-tails than those of the modern world, and 

 tiiat their fructification wixs equisetaceoos and of the 

 form known as CkilanMstackys. 



We have already seen that noble tree-ferns existed in 

 the Erian jteriod, and these were continued, and their 

 number and Tariety greatly extended, in the Carbonifer- 

 ous, In regard to the structure of their stems, and the 

 method of supporting these by aSrial roots, the tree-ferns 

 of all ages ha^e been nearly alike, and the form and 

 structure of the leases, except in some oomparataTely rare 

 and exceptional type^ has also been much the same. 

 Any ordinsury observer e3amining a collection of coal- 

 fbrmation f^ns recognises at once their kinship to the 

 &militff brackens of our own time. Their fructification 

 is, unfortunately, rarely preserved, so that we are not 

 able, in the case of many species, to speak confidently of 



Fio. 50. — Stams of OiilimoJfmdnH and tissnes nu^iufied (Nov* Sootia'). 

 €, i, C>st3 of uds in smdstoDe, 'nith woo4f euTelopa (reduced), 

 c, i, Woodt; ti^ua (higUy magnified). 



their affinities with modern forms ; but the knowledge of 

 this subject has been constantly extending, and a suffi- 

 cient amount of information has been obtained to enable 

 us to say ^mething as to their probable relationships. 

 (Kgs. 51 to 55.) 



The families into which modern ferns are diyided are, 

 it mnst be confessed, somewhat artificial, and in the case 



