﻿ti6 



REPRODUCTIVE STRUCTURES. 



parallel to the upper surface, there are from three to five small vascular bundles 

 comparable to those of the leaf bases, though much reduced. In the much-lignified 

 condition and presence of the very peculiar striate mesophyll, however, the bract 

 structure varies markedly from that of the leaf bases. 



c 



S.3&7X.2-0. 



T272S.¥/*t,K"o, 



Fig. 60.— Cycadeoidea Paynei (?). T. 272. S. 414. Details of bract structure. 



A. Transverse section through upper seed-bearing portion of ovulate strobilus, cutting imbricating bracts and showing by darker 

 shading the relative development of the heavy-walled tissue of the bract, facing toward the seed cone. X 2. 



B. Slightly diagrammatic vertical longitudinal section through much-expanded distal portion of bract, as shown in A lying appressed 



to the summit of an ovulate cone. >20. Further towards their bases the bracts are slenderer and all the cells of the ground tissue 

 lengthen greatly, in particular the subepidermal cells, which are smaller, long. bast-like, and with far less closely placed or no 

 scalanform markings. I, Upper lignified and only partially preserved region next to cone ; g, gum duct; b, vascular 

 bundle ; s, scalariform ground tissue. 

 C Same section as A. Portion of a single bract, greatly enlarged, showing the heavy-walled hypodermal sclerenchyma, and 

 beneath it the much-lignified ground tissue traversed by gum canals and a vascular bundle with only the xylem preserved. 

 The non -conserved phloem area beneath the xylem is left blank. > I 10. 



1NTERSEM1NAL SCALES. 



Distribution and form. — As already noted, the space between and about the 

 seed pedicels is everywhere solidly packed with interseminal scales. Normally five 

 or six of these scales surround each seed pedicel throughout the central portions of 

 the cone, but towards the periphery the pedicels increase in number to the entire 

 exclusion of fertile organs, the outer portions of the cone in all cases at last entirely 

 consisting of scales packed in close order from several to many layers deep, the 



