390 ABIETINEAE [CH. 



proposed the name Z. Henslowi : their Abietineous nature was first 

 recognised by Corda^, and Carruthers^ subsequently gave some 

 account of the internal structure and employed the generic name 

 Pinites. The discovery of additional specimens in situ enabled 

 Carruthers to assign P. macrocephalus to Eocene beds at the 

 junction of the Woolwich and Thanet beds with the London Clay. 

 Both Carruthers and Gardner^ retain both specific names, but an 

 examination of the specimens convinces me that there are no 

 difierences worthy of specific recognition. The following brief 

 account is based on an examination of sections in the British 

 Museum and in part on notes supplied by Mr Dutt of Queens' 

 College, Cambridge, who is preparing a fuller account of the 

 material*. The cones are ovoid-cjdindrical and obtuse; the 

 weathered surface (fig. 783) shows slightly convex polygonal areas 

 without any trace of a central umbo. The axis is slender in com- 

 parison with that of most recent species of Pinus; the stele includes 

 a fairly large pith of thick-walled cells surrounded by a vascular 

 cylinder in which foliar gaps are formed by the exit of the double 

 sporophyll-traces. It is noteworthy that no resin-canals occur in 

 the xylem. A ring of large resin-canals lined with thin-walled 

 epithelial cells occurs outside the phloem. The cone-scales are 

 given of! almost at right-angles and then bend sharply upwards 

 and become slightly broader near the surface of the cone (fig. 

 784, B). In one section a portion of a subtending bract-scale was 

 recognised. The seminiferous scales are composed of thick-walled 

 cells and contain idioblasts like those in Araucarian leaves, also 

 resin-canals : two ovules occur in a depression near the base of the 

 scales. The sporophyll-trace divides in the scale into several bundles, 

 and in places there are indications of a second series of inversely 

 orientated strands. The comparatively large ovules, nearly 1 cm. 

 long, are attached by a short stalk, and in places the remains of a 

 wing can be seen. Although the integument is thick and lignified 

 and the micropyle closed there are no embryos and no indication 

 of archegonia in the partially preserved nucellar tissue. In the 



» Corda in Reuss (46) B. 

 - Carruthers (662) pp 536^ 540, pi. xxi. 

 ^ Gardner (86) pp. 63, 66, PI. xiv. 

 « Butt (16). 



