﻿1 7 8 



REPRI 1DUCTIVE STRUCTURES. 



these axes passing from the summit of the trunk to the medulla in the radial longi- 

 tudinal plane show them to consist simply in heavy, flattened, barrel-shaped bract- 

 bearing bodies surmounted by long 

 and dense ramentum. There is here 

 in fact a nearly full grown pedun- 

 cle, bearing rather small but long 

 bracts throughout nearly all of the 

 distal two-thirds of its entire length ; 

 and the only suggestion of the 

 subsequent development of a ter- 

 minal fruit consists in some young, 

 small, low, and not very distinct 

 growths, forming a sort of api- 

 cal asteriation deeply packed in 

 ramentum. This asteriation does 

 not appear to be formed entirely of 

 the youngest bracts, which of course 

 form the terminal members of a 

 spiral series, and hence may be held 

 to mark the position where a fruit 

 would eventually have formed under 

 normal conditions of growth; though 

 it may well be that the growth of 

 these particular axes has been in 

 some way checked. In any case, 

 however, it is pretty dear that early 

 growth of the peduncles to a nearly 

 normal length and sice took place 

 be/ore any well-marked strobilar 

 development, and it seems that this 



must have been the habitual mode of 

 early fruit growth and emergence in 



these plants. 



The structure of the peduncle is 



essentially that of much more mature 



forms. There is the usual woody 



cylinder, inclosing a peduncular 



medulla, and surrounded by a cor- 

 tex traversed by delicate bundles 



running out to the bases of the 



bracts, but not nearly so distinct as 



are leaf-trace bundles. As in all the 



peduncles, this is practically a repe- 

 tition of the trunk structure itself, 



whence these fruit axes are simply 



Fig. 95.— Cycadeoidea dacotensis. T. 214. F. VI. S. 512. 

 Radial longitudinal section of trunk, and neatly median 

 longitudinal section of young axis of fructification and 

 surrounding leaf bases, as borne near the summit of the 

 trunk. In about the same stage of growth as Fruit IV of 

 T. 214. Natural size. 



b. Bracts ; r, large receptacle at the apex of which only the bracts 



are as yet prominent; 1, leaf bases; p, bundle system of the 



peduncle as seen to extend through the cortical parenchyma ; 



c, cortex ; w, woody cylinder ; m, medulla. For transverse 



sections see figure 95a. 



