T^-7^ 



r 



i i 



y ; \ 



II p i 



I 



136 



THE GEOLOGICAL HISTORY OF PLANTS. 



relation, no doubt, to the equable climate of the period. 

 There is not much evidence that they grew with the Si- 

 gillariae in the true coal-swamps, though some specimens 

 have been found in this association. It is more likely 

 that they were in the main inland and upland trees, and 



B d 



Fig. 61. — Trigonocarpum Hooheri, Daw- 

 son, from "the coal-measures of Cape 

 Breton. Probably the fruit of a Tax- 

 "' ine tree, a, Broken specimen magni- 



fied twice natural size, b, Section magnified : a, tiie testa ; ft, the teg- 

 men; c, the nucleus; d, the embryo, c, Portion of the surface of the 

 inner coat more highly magnified. 



', ■■< 



that in consequence they are mostly known to us by 

 drifted trunks borne by river inundations into the seas 

 and estuaries. 



A remarkable fact in connection with them, and show- 

 ing also the manner in which the most durable vegetable 

 structures may perish by decay, is that, like the Cordaites, 

 they had large piths with transverse partitions, a struct- 



