190 CONIFEBALES [CH- 



are regarded by the author of the genus as undoubted repre- 

 sentatives of the Araucarineae, a determination that is hardly con- 

 sistent with the aifinity implied by the generic name. The species 

 P. aipressoides, from Yorkshire and the Cretaceous lignites of 

 New Jersey, is characterised by the restriction of pits to the radial 

 wall of the. medullary-ray cells, the absence of Sanio's rims, the 

 presence of scattered xylem-parenchyma, and by the occurrence 

 both of scattered and crowded pits on the tracheal walls. More- 

 over in this species the phloem shows an alternation of hard and 

 soft elements. The affinity suggested by these features would 

 seem to be to Cwpressinoxylon. On the other hand, Paracwpres- 

 sinoxylon cedroides, founded on material from the Yorkshire coast, 

 is characterised by the Abietineous pitting of the medullary-ray 

 cells, an admixture of scattered and compressed bordered pits on 

 the radial walls of the tracheids, scattered xylem-parenchyma, no 

 alternation of hard and soft bast, and by the absence of any 

 sclerous cells in tlie pith. This species also illustrates the occur- 

 rence of resin-canals in wounded regions of the wood. The refer- 

 ence of both these species to the Araucarineae, chiefly because of 

 the absence of Sanio's rims, though consistent with the principle 

 that this character is all important, implies the neglect of other 

 characters, more especially the nature of the medullary-ray pitting, 

 which in the case of recent Conifers are unquestionably of taxo- 

 nomic importance. The species P. cedroides should not, in my 

 opinion, be included with P. cupressoides in one genus ; it is pro- 

 bably more closely allied to the Abietineae than to any other 

 family. It should, however, be remembered that pitting of the 

 horizontal and tangential walls of medullary-ray cells is a feature 

 that is not confined to the Abietineae ; it occurs also in some recent 

 Junipers and the extinct genera Protocedroxylon and Thylloxylon. 



CujJiessinoxylon liasintim Lignier. 



This Liassic species ^ from Orne, France, is founded on the wood 

 of a pentarch and hexarch root : the bordered pits on the radial 

 walls of the tracheids are usually in one row, occasionally in two 

 opposite series ; smaller pits occur on the tangential walls ; medul- 

 lary rays 1—5 cells deep with a few ovoid-oblong pits, often simple 



1 Lignier (07=) p. 306, PI. xxi. figs. 58—61; PI. sxin. fig. 83. 



