OF LOWER GREENLAND PLANTS. 175 



Barber does not give an actual diagnosis, but summarises his 

 elaborate description as follows : " Specimens 1-2 inches in 

 diameter, with distinct central or excentric pith. Rings of 

 growth well marked, averaging 1-2 mm. wide, composite, each 

 with 2-6 bands of narrow, dark, summer elements. From the 

 arrangement of the cells in the rings, the specimens are con- 

 sidered to be young branches and roots. Pith well preserved, 

 diameter in branches '9 mm., in roots '3 mm. to '4 mm., cells 

 increasing in size towards the centre, 10 /A to 50 /A in diameter, 

 copiously pitted, with large triangular intercellular spaces 

 5-15 ft across. Medullary sheath : in the roots the rows of 

 tracheides pass directly into the cells of the pith, in the branches 

 they terminate in small groups of cells irregularly arranged. 

 Spring tracheides not differing much in branch and root, tan- 

 gential width 12-25 //,, radial 17-22 ft ; summer tracheides in 

 the branches, radial diameter 10-11 ft, averaging 4-6 rows, in 

 the roots radial diameter 12 ft, averaging 2-4 rows. Bordered 

 pits in a single row (rarely double in roots), free and rounded 

 in branches, often touching and compressed in roots, outer 

 diameter 7-14 ft, inner 3-5 ft. Tangential pits frequent, 

 occurring in 2-7 rows of summer cells, outer diameter 5-7 ft, 

 inner 2-3 ft. Medullary rays simple, usually one, occasionally 

 two cells broad, 1-16 cells high, the average being 2-3. Cells 

 of ray 15-20 /x high, 12-16 ft broad, radial length various, 

 covering 2-6 tracheides. Proportion of medullary ray-tissue 

 to the rest of the wood about 1 : 30. llesin-tissue, consisting 

 of isolated rows of parenchymatous cells, abundant, equally 

 distributed. Length of cells various, tangential width 19-28 ft, 

 radial 11-20 ft." 



The author adds : " It has not been found possible to place 

 this wood under any species of Cupressinoxylon already described. 

 The peculiarity of the rings of growth is probably in itself 

 sufficient to establish a new species. Besides this, however, 

 the youth of the specimens and the detailed examination to 

 which they have been subjected leave few points of comparison 

 with known fossils. From the frequent occurrence of this type 

 of wood in the Lower Greensand of the Isle of Wight, I have 

 decided to call it Cupressinoxylon vectense." 



The " composite rings," while they are particularly well 

 marked and very characteristic of C. vectense, are not entirely 



