PAST HISTORIES OF PLANT FAMILIES 



95 



TOWS by a normal cambium (see p. 66), and the tracheae 

 so formed had characteristic rows of bordered pits (see 

 fig. 62B). The wood comes nearer to that of the living 

 .Araucarias than any other, and indeed the numerous 

 pieces of fossil wood of this type which are known from 

 all the geological periods are called Araucarioxylon? A 

 double strand goes out from the main mass of wood, 

 which afterwards divides and subdivides to provide the 

 numerous bundles of the leaf. 



In the case of these fossils we are 

 fortunate enough to have the fructifica- 

 tions, both male and female, in a good 

 state of preservation. As in other 

 Gymnosperms, the male and female 

 cones are separate, but they differed 

 Jess from each other in their arrange- 

 ment than do those of any of the living 

 types hitherto mentioned. They can 

 hardly be described as true cones, 

 though they had something of that 

 nature; the seeds seem to be borne on 

 special short stems, round which are Fig. 63. c 

 .also sterile scales. In the seed and Pith of Cordait ^ the 



! ... , 1 /-> constrictions correspond- 



the way it is borne perhaps the Cor- ing to discs of solid tissue 

 daiteae may be compared more nearly across the cavity 

 with the Taxeae than with the other 

 groups. A seed, not yet ripe, is shown in slightly dia- 

 grammatic form in fig. 64, where the essential details 

 are illustrated. The seeds of this family sometimes 

 reached a considerable size, and had a fleshy layer 

 which was thick in comparison with the stone, and ex- 

 ternally comparable with a cherry though, of course, of 

 very different nature in reality, for Cordaites, like Taxus, 

 is a Gymnosperm, with simple naked seeds, while a 

 cherry is the fruit of an Angiosperm. 



1 The addition of -oxylon to the generic name of any living type indicates that we 

 are dealing with a fossil which closely resembles the living type so far as we have 

 .information from the petrified material. 



