XXXIX] PSETIDOCYCAS 563 



parallel ridges on the upper surface and to these are attached at 

 a wide angle the broad bases of narrow linear pinnae reaching a 

 length of 9 cm. and a breadth of 2—3 mm. (fig. 617). The pinnae 

 are thick and separate and each has a double 'midrib' consisting 

 of two parallel Hues (fig. 617, B) which are occasionally replaced 

 by one. The so-called double 'midrib' represents the two promi- 

 nent ridges bordering the groove. The stomata, confined to the 

 median groove, are approximately circular and the short epidermal 

 cells have sinuous walls ^. 



Pseudocycas Steenstrwpi (Heer). 



Nathorst refers this species, described by Heer as Gycadites, 

 from the Cenomanian of Greenland, to Pseudocycas on the ground 

 that the epidermal cells are like those of P. Steenstrwpi and the 

 stomata are confined to a median groove. Heer figures an im- 

 pression in close association with the frond of this species which 

 he identifies, without any adequate reason, as a carpellary leaf Hke 

 that of a Cycas. 



Pseudocycas Saportae (Seward). 



It has recently been shown by Miss Holden that this Wealden 

 Enghsh species^ has the epidermal characters of Pseudocycas. 

 In external form it agrees closely with Gycadites tenuisectus Sap.^ 

 from Lower Cretaceous rocks in Portugal, but nothing is known 

 of the epidermal features of the latter type. The rachis is broad 

 and flattened and bears alternate or sub-opposite pinnae of 

 uniform breadth attached at right-angles or obliquely to its upper 

 surface (fig. 618). The pinnae are 6 — 7 cm. long and about 

 1 mm. broad ; their bases are sHghtly expanded and the apices 

 sharply pointed. Miss Holden* finds that the median rib is some- 

 times double and that the middle region of the lamina is covered 

 with stomata ; the epidermal cells have siniious walls and stomata 

 occasionally occur on each side of the main median stomatal area. 

 Dr Halle ^ of Stockholm, who has examined cuticular prepara- 

 tions made from Enghsh specimens, confirms Miss Holden's 



' Nathorst (07^ Pis. I.— ni. 



2 Seward (95) A. p 29, PI. Ii. fig. 7; PI. VI. fig. .5; PI. viii. fig. 2. 



= Saporta (94) B. p. 171, PI. xxxii. * Holden, R. (14^). 



5 HaUe (55), p. 502. 



36—2 



