OF LOWER GREEXSANI) PLANTS. 221 



V. 5446 a. Transverse section of the above. The tissue is very 

 imperfectly petrified. So far as it goes the specimen 

 agrees with the others described for this species, 

 though its identification is a little uncertain, as ib 

 was so poorly petrified that it was not thought worth 

 while to have longitudinal sections cut. 

 Lower Greensand ; Woburn Sands. 



Transferred from the Botanical Dept. 



V. 5460. A small knotted branch 15 cms. long and of irregular 

 diameter. At the straight end, from which the 

 sections are cut, the stem is 1/8 xl'o cm. in diameter. 

 Externally the decorticated axis shows the woody 

 fibre and several " knots " and the bases of branches. 

 The silicified medium is locally iron- stained in the 

 sections. 



V. 5460 a, b. Transverse sections of the above. The pith-cells 

 are very incompletely preserved. The primary wood 

 lies in large shallow bundles, which are not very well 

 preserved and are further obscured by black mineral 

 granules. The rings of secondary wood are locally 

 well preserved, and show definite, though narrow, 

 zones of autumn wood. All through both spring arid 

 autumn wood, large resin-containing xylem-paren- 

 chyma cells are very conspicuous. The medullary 

 ray-cells are also large and well preserved (cf. text- 

 fig. 60). 



V. 5460 C. Radial section of the above. Locally this is very 

 well preserved, and large numbers of the ray-cells 

 show the pittings of their radial walls. In the great 

 majority the pits are large roundish pits, one per 

 tracheid-field (cf. text-fig. 61), in other cases there 

 are two large pits per tracheid-field, one above the 

 other. The resin-containing xylem-parenchyma is 

 conspicuous, with rectangular transverse walls. In 

 general, the radial section agrees with that figured for 

 the type (text-fig. 61). 



