OF LOWER GBEENSA2TD PLANTS. 173 



round pits often being separated from their neighbours by a 

 distance nearly as great as their own diameter. In other cases 

 the pits lie so close together as to be somewhat crushed, and 

 there is an occasional doubling of the row as in text-fig. 49, b. 

 The pit-pore is circular and sometimes very large, 3-5 fj.. The 

 average diameter of the bordered pits is given by Barber, after 

 numerous measurements, as 13-14 p. Bordered pits are present 

 in the tangential walls of the autumn wood. 



Wood-parenchyma containing large quantities of black resinous 

 remains is very conspicuous. In transverse section the elements 

 lie isolated among the tracheids, and are of about the same size, 

 both radially and tangentially, as the elements adjacent to 

 them. In radial view the transverse walls are horizontal, with a, 

 slight constriction just at the division of the cells (text-fig. 50), 

 In tangential section these cross-walls are seen to lie at a low 1 

 angle, the terminal walls of a cell-row being acutely pointed 

 and resembling a trachcid, but for the absence of pitting in the 

 wall. 



Itcsin-cai'als, normally, are entirely absent. In a specimen 

 1 found in 1912, however, traumatic canals are numerous. 



Medullary rays consist of uniform elements, without any 

 ray-tracheids. In transverse section the tangential diameter 

 of the rays is rather less than that of the adjacent tracheids ; 

 in radial extension the elements correspond to from 2-6 

 t rucheids. Barber observed pits on the radial walls, but does 

 not figure them ; he says " In both radial nd tangential 

 sections these [pits] were seen to be simple. In shape they 

 were oval and obliquely placed, usually two or one per cell, 

 occasionally three or more, rarely four. The higher numbers 

 were, as usual, on the outer cells, the middle cells having 

 frequently one pit each. This is in accordance with the Sequoia 

 type of wood.'' As since the time this was written it has been 

 recognised that the pitting of the medullary ray-cells is perhaps 

 the most important single feature in a wood, I am giving an 

 illustration of these pits in the type-specimen, the sections of 

 which were kindly lent me for the purpose by Prof. Seward 

 (text-fig. 50). 



Hoots of this species are described by Barber as having a 

 pith *3-'4 mm. in diameter. The primary wood in the specimens 

 Barber considers as roots is not in definite bundles, but passes 



