yo UESCRIPTIVE CATALOGUE 



occluded by tj'loses. Medullary rays numerous, distant 2-9, 

 chiefly 3-5 tracheid-rows, uniseriate except those containing 

 resiu-canals. Medullary ray-cells frequently larger than the 

 adjacent tracheids, averaging 30 p. in tangential diameter. 

 Hays complex ; parenchyma-cells with thickened or curved 

 end-walls, single large pits in tracheid-field. Kay- tracheids 

 above and below and in interspersed bands in the higher rays. 

 Ray-tracheids simple, low ; outline very little distorted, pitted 

 by scattered round bordered pits. Multiseriate rays with resin- 

 canals not numerous. 



HoKizoy. Lower Greensand. 



LOCALITY. Ightham, Kent. 



TYPE. V. 1440, and slides cut from it ; British Museum 

 (Nat. Hist.). 



FINDER. John Hale, jun., 1886; slides cut, 1912. 



DESCRIPTION. The single specimen from which this species is 

 described is a good-sized portion of secondary wood which does 

 not include any sign of either pith or bark. The mass of the 

 secondary wood is in the form of a rough wedge, 27 cm. long 

 by 13 X 6 cm. The disposition of the rings is such that the 

 whole trunk could not have been less than 18 cm. in diameter. 

 The cell-structure is well silicified and slightly iron-stained: 

 free from matrix, the texture of the wood shows up well to the 

 naked eye. 



TOPOGRAPHY OF THE STEM. Pith and bark are both absent. 



Growth-rinys are very well marked and of large size. The 

 thickness of each ring averages from about 4 to 6 mm., con- 

 sisting of from 120-180 cells. It is difficult to make accurate 

 counts of the exact number of cells, because about ^ of each 

 ring, the thinner-walled spring wood, is very much crushed and 

 distorted. Though this crushing serves to make the annual 

 rings very noticeable, the actual difference between the spring 

 and autumn wood is not great. 



The general character of the iwod is seen in PI. IV. The 

 uniform rows of tracheids consist of elements somewhat rounded 

 off from each other. Parenchyma-cells are grouped round the 

 resin-canals, which are scattered singly throughout the whole 

 of the wood (PI. IV, fig. 1, r.c.), and also tend to lie in rows of 

 3 or more towards the inner side of the autumn wood (PL IV, 

 fig. 2, r.c.a.). Scattered through the wood are elements filled 



