CHEIROSTROBEAE 



119 



of the wood was evidently centripetal, 1 as in Spheno- 

 phyllum or in the Lycopodiaceae. The rest of the 

 tracheae bear multise,riate bordered pits, as is com- 

 monly the case in Sphenophyllum. There was no 



Fig. 51. — Cheirostrobus pettycurcnsis. Transverse section of axis of cone, x, xylem 

 with twelve prominent angles ; It, leaf-traces, one undivided, the other divided into 

 three ; l&, leaf-trace, already divided into four bundles, and the inner one subdividing ; 

 sp, bases of sporophylls ; sm, sporangia. X about 8. Phil. Trans., S. Kidston 

 Coll. 84 A. 



pith, the wood extending to the centre of the stele, 

 though intermixed with conjunctive parenchyma. 



The cortex presents no points worth special notice, 

 except that it contained long sacs, perhaps of a secretory 

 nature. The course of the leaf-trace bundles, however, 

 is highly characteristic. They start from the angles 



1 There is some evidence that a minute amount of primary xylem was 

 developed centrifugally- 



