REVISION OF THE ENGLISH WEALDEN FLORA 



51 



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Fig. 17 A-B Ginkgoires garlickianiis sp. nov. A, distribution and 

 orientation of stomata on lower surface; B, distribution and orientation 

 of stomata on upper surface; both from holotype, V.64548, x 50. 



Bay. However, the stomata of C. anguae are strictly longitudinally 

 orientated on both surfaces, are arranged in files rather than scat- 

 tered, are never papillate and have 2 distinct polar subsidiary cells. 

 Amongst Lower Cretaceous floras from elsewhere the two species 

 Ginkgoites brauniana (Dunker) from the Lower Cretaceous of Ger- 

 many (Watson etal 1999) and Ginkgoites pluripartita (Schimper), a 

 species widely distributed in the northern hemisphere (Watson et al 

 1999), show similarities to the English species. The narrow, 

 dichotomizing segments of G. weatherwaxiae are similar to those 

 seen in some specimens of G. brauniana, which differs however in 

 having stomata confined to the lower surface and has lower ordinary 

 epidermal cells bearing small median papillae. The less divided 

 leaves of G. pluripartita bear a resemblance to the wide leaf seg- 

 ments of G. nannyoggiae, but G. nannyoggiae lacks the conspicuous 

 venation of G. pluripartita and the two differ in cuticular details such 

 as the appearance of the stomata. 



Ovule attributed to Ginkgoites weatherwaxiae 



Figs 20, 21 



Description Compressed oval cuticular structure, 0.7 mm long 

 and 0.4 mm wide, comprising an inner layer composed of the 

 megaspore membrane and associated cutinized gametophytic tis- 

 sue, surrounded by the nucellar cuticle with gap of up to 40 |im 

 between the two. Inner layer thickly cutinized with vesicles 1.3- 

 5.4 |im in diameter irregularly scattered throughout; aggregations 

 of vesicles often in centre of ill-defined polygonal cells about 60 

 pm across. 



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Fig. 18 A-C Ginkgoires garlickianus sp. nov. All upper cuticle. 



A, holotype, single stoma obscured by subsidiary cell papillae. V.64548, 

 LM, X 500; B, papillate stomatal pit viewed from outside, V.64549, 

 SEM, X 750; C, holotype, inner surface of upper cuticle showing single 

 stoma. V.64548, SEM, x 750. 



Nucellar cuticle thin. 80 |jm wide at chalaza; mucronate apex or 

 beak extending 80 |jm above inner layer, forming pollen chamber. 

 Cells straight-walled with smooth outer periclinal walls, around 100 



