9 o ANCIENT PLANTS 



like those of the lower Gymnosperms and of several fossil* 

 types. Those, however, who hold to the view that the 

 Abietineae are primitive, see in the Taxecz the latest and 

 most modified type of Gymnosperm. 



It will be seen from this that there is no lack of 

 variety regarding the interpretation of Gymnosperm 

 structures. 



The Gymnosperms do not stand in such an isolated 

 position as do the Angiosperms. Whatever the variety 

 of views held about the details of the relative placing 

 of the families within the group, all agree in recog- 

 nizing the evidence which enables us to trace with 

 confidence the connection between the lower Gymno- 

 sperms and the families of ferns. There are many 

 indications of the intimate connection between higher 

 and lower Gymnosperms. Between the series exist 

 what might be described as different degrees of cousin- 

 ship, and in the lower groups lie unmistakable clues to 

 their connection with more ancient groups in the past 

 which bridge over the gaps between them and the ferns. 



For the present, however, let us confine ourselves to- 

 the history of the more important Gymnosperms, the 

 discussion of their origin and the groups from which they 

 may have arisen must be postponed until the necessary 

 details about those groups have been mentioned. 



To a consideration of the living families of Araii- 

 carecz, Abietinece, Cupressecz, and Taxe<z we can allow 

 but a short space; their general characters and appear- 

 ance are likely to be known to the reader, and their 

 details can be studied from living specimens if they 

 are not. For purposes of comparison with the fossils, 

 however, it will be necessary to mention a few of the 

 principal features which are of special importance in 

 discussing phylogeny. 



The ARAUCARIACE^E are woody trees which attain a 

 considerable size, with broad-based, large leaves attached 

 directly to the stem. In the leaves are a series of numer- 

 ous parallel vascular bundles. The wood cells in micro- 



