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INTRODUCTORY. 



are also distantly, though distinctly enough, analogous to the bracts surrounding 

 the fruits of the Cycadeoidete. ( Cf. figures 4-6 and various illustrations in the ninth 

 and other chapters.) 



It is, however, in fructification that extraordinary diversity is found, although, 

 perforce, the further back we go in the cycadean, cycadeoidean, and cycadofilicinean 

 series, the more nearly do the respective sporophytes agree with the accompanying 

 foliage leaves, and the more pteridophytic becomes the structure position and form 

 of both. Moreover, in the most specialized of the existing forms, as well as in the 

 Cycadeoidese, both male and female fruits are to be regarded as much modified 

 branches with elongate stems or peduncles. In the Cycadeoidece the peduncles, 



Fig. 5. — Angioptens Teysmanniana de Vnese. / ,'„. 



A, medium-sized spherical to conical trunk (or comparison with the preceding forms. Fronds bipinnate as in Bowenia, 



venation (B) as in Stangeria, From Engler and Prantl. 



being interpolated among the leaf bases, thrust these aside and finally destroy their 

 regular order, so that it should be possible to determine whether a given trunk has 

 ever borne fructifications or not. Later in the volume this point will be discussed 

 more fully in treating of the generic value of Cycadeoidea and Bennettites, the former 

 having been hitherto considered as being without and the latter as having lateral 

 fructifications; for the present it is merely intended to consider the various simple- 

 stemmed trunk forms, branching types, and habits of growth. 



The fossil cycads, like the living forms, although bearing wide-spreading fronds, 

 are, as compared with other trunk-forming plants, small or even pygmic. In the 

 living forms the extremes lie between the epiphytic Zamias of Panama and eastern 

 Peru, together with the small underground and much-branched trunks of the 

 Florida Zamias on the one hand, and on the other the East Indian Cycas, which 



