﻿OVULATE CONES. 



119 



Histology. — A transverse section cut exactly at the level of insertion on the 

 receptacle shows, wherever the tissue of the latter is preserved and has not been 

 disrupted during fossilization, that the numerous lignified elements of the pedicel are 

 seated over parenchyma cells of large size {cf. plate xxcui, photograph 7). Through- 

 out the pedicel runs a single central concentric vascular bundle surrounded by a 

 well-marked bundle sheath, which is enveloped by a wide outer region of elongate 



Fig. 61. — Cycadeoidea Wielandi. S. 103, T. 393. X 100. Transverse sections showing organiza- 

 tion of the seed stems, or pedicels, and interseminal scales, as cut a short distance beneath seed zone. 



A, Seed slem. consisting in a single concentric bundle inclosed in a bundle sheath enveloped in a heavy large-celled 

 cortex, not all of which is shown. See C. 



B, An interseminal scale as inclosed by the cortical region of two seed stems above, and by several other interseminal 

 scales below. Note that the interseminal scale ends in an outer heavy epidermal layer. This layer belongs to the 

 sterile organs or scales, because it is double where these are adjacent and single where a seed stem adjoins. The 

 sterile scales hence consist in a central concentric bundle inclosed in a few cortical cells and a heavy epidermis. 



C, A single seed stem cut near its summit and surrounded by interseminal scales with diminished phloem and marked 

 increase in lignificabon. 



sclerenchyma cells or cortex. As already explained in the description of the 

 interseminal scales, just outside this cortex is the closely appressed layer of smaller 

 epidermal cells, which is a true portion of the interseminal scales and only appears 

 to be the final outer portion of the seed pedicels, because the latter are entirely 

 enveloped in scales. Throughout the apical region of the pedicels the cells of the 

 cortex are large, but quite regularly decrease in size and correspondingly increase in 

 number all the way to the pedicel base. The central bundle is seen to consist of a 



