OF LOWER GREEXSAND PLANTS. 265 



siderably thickened and pitted. The pits in the radial walls 

 are numerous, and bordered in contact with the vessels ; those 

 in the end-walls between adjacent ray-cells being like those 

 described as " abietinean " among the Conifers. The terminal 

 cells of the rays are slightly higher and more irregular than 

 the others (text-fig. 77, e.), but the difference between them arid 

 the adjacent cells is so trifling that the rays may be said to be 

 entirely uniform, and are a great contrast to those in A^tiana 

 (text-fig. 92, p. 291). 



AFFINITIES. The most noticeable feature of this wood is the 

 simple uniform rays, which are entirely uniseriate. Several 

 families and a number of isolated genera of Angiosperms have 

 uniseriate rays, which are by some writers (see Eames 1910, 

 Thompson 1911, etc.) considered to be a primitive feature in 

 Dicotyledons. 



Among the species with uniseriate rays, those which in other 

 respects also appear to come nearest to the fossil, are species of 

 Franlclinia, Euonymus, Alnus, and Salix. Franklinia alta- 

 mabra is in all its details noticeably like the fossil, save that a 

 few of its medullary ray-cells show long scalariform pits. 

 While I have not detected these in C'antia, it is not impossible 

 that they may have been present, though, as the ray-pitting is 

 so exceptionally well preserved, it seems likely that they 

 would be present in the sections if they had been a feature of 

 the plant. Some species of Euonymus also come very near the 

 fossil and have, like it, large pits in the fibre-tracheids, in 

 which particular they come nearer the fossil than does Alnus 

 with its smaller-pitted fibre-tracheids. Both the genera Alnus 

 and Salix contain species which seem very close to the fossil, 

 though they both contain also a large proportion of species in 

 which the vessels are generally in series instead of isolated as 

 is the case in the fossil. 



Regarding the affinities of Cantia, Mr. L. A. Boodle, of Kew, 

 who has kindly looked at the sections, writes to me as follows : 

 " Affinity with Betulaceas might be suggested as possible, 

 while holding oneself ready to discard this suggestion should a 

 more significant agreement with some other wood be observed. 

 Considering the age of the specimen, it is perhaps to be sus- 

 pected that its structure might incline towards a primitive 

 character in some of its details as compared with its nearest 



