THE CARBONIFEROUS FLORA. 



133 



with broad lateral wings for flotation in the air, or in 

 some cases with a pulpy envelope, which flattens into a 

 film. There seem to have been structures of both these 

 kinds, though in the state of preservation of these curious 

 seeds it is extremely difficult to distinguish them. In the 

 first case they must have been intended for dissemination 

 by the wind, like the seeds of spruces. In the latter case 

 they may have been disseminated like the fruits of taxine 

 trees by the agency of animals, though what these were 

 it would be difficult to guess. These trees had very great 

 reproductive power, since they produced numerous seeds, 

 not singly or a few together, as in modern yews, but in 

 long spikes or catkins bearing many seeds (Fig. 59). 



It is to be observed that the Cordaites, or the Cor- 

 daitince, as they have been called, as a family,* constitute 

 another of those intermediate groups with which we have 

 already become familiar. On the one hand they approach 

 closely to the broader-leaved yews like Gingko, Phyllo- 

 cladus, and Podocarpus, and, on the other hand, they 

 have affinities with Cycadaceae, and even with Sigillariae. 

 They were beautiful and symmetrical trees, adding some- 

 thing to the variety of the rather monotonous Palaeo- 

 zoic forests. They contributed also somewhat to the ac- 

 cumulation of coal. I have found that some thin beds are 

 almost entirely composed of their leaves, and the tissues 

 of their wood are not infrequent in the mineral charcoal 

 of the larger coal-seams. There is no evidence that their 

 roots were of the stigmaroid type, though they evidently 

 grew in the same swampy flats with the Sigillariaa and 

 Calamites. 



It may, perhaps, be well to say here that I believe 

 there was a considerably wide range of organisation in the 

 Cordaitinae as well as in the Calamites and Sigillariae, and 

 that it will eventually be found that there were three lines 



* Engler ; Cordaitees of Renault. 



