REVISION OF THE ENGLISH WEALDEN FLORA 



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Fig. 13 A-C Cinkgoites nannyoggiae sp. nov. All show holotype, 

 V.64545, from Fairlight Clays of the Ashdown Beds, Galley Hill, 

 Sussex. A, stomatal distribution for lower cuticle, x 50; B, upper cuticle 

 showing pitting of anticlinal and outer periclinal walls of epidermal 

 cells, a stoma (left hand side) with ill-defined subsidiary cells and an 

 oval scar overlying two epidermal cells, x 400; C, a single stoma on the 

 lower cuticle; inner periclinal cutinization of subsidiary cells and part of 

 an encircling cell (right hand side) giving darker appearance; outline of 

 guard-cell dorsal plates unclear in places, x 400. 



contrasts greatly with that of the upper surface. It bears numerous 

 scattered stomata and has a densely papillate surface (Figs 12D; 

 14D; ISA, B). The ordinary epidermal cells, which bear the same 

 pitting seen in the upper cuticle (Fig. 15F), are isodiametric (Fig. 

 15C) or longitudinally elongate and randomly arranged (Fig. 15 A), 

 or in vague longitudinal files (Fig. 14D). The bulging outer surface of 

 each cell bears a large, prominent, hollow papilla (Fig. 15 A, B). 

 Although veins are not clearly detectable on the leaf surface, vein 

 courses are indicated on the lower cuticle by the absence of stomata 



47 



and less pronounced papillae in some specimens (Fig. 1 2D). There is 

 not enough information to indicate venation for a whole segment 

 width but the specimen in Fig. 1 2D shows at least 12 veins. Fig. 15D 

 shows the typical surface appearance of the stomatal apparatus 

 forming a smooth flat area between the surrounding papillate cells. 

 The papillae on the subsidiary cells are smaller, flattened and pro- 

 trude over the oval stomatal pit. Fig. 1 5E shows two stomata in which 

 the subsidiary cell papillae are larger and give an appearance similar 

 to that of the ordinary epidermal cells. The 6 or so subsidiary cells of 

 each stoma are less pitted than the ordinary epidermal cells (Fig. 

 1 5F). The guard cells tend to be obscured in the light microscope by 

 the strong papillation of the other cells but an inner view in the SEM 

 (Fig. 15F) shows them to have narrow dorsal plates which bear fine 

 radiating striae on the inside. This stoma appears to have true 

 encircling cells adjacent to the two subsidiary cells on the right hand 

 side, and encircling cells are also shown in the stoma in Fig. 13C. 



The fragment of lower surface cuticle in Figs 12D, I4D shows 

 what is thought to be post-mortem arthropod damage: there is no 

 reaction tissue around the edge of the regular circular hole. 



Comparison. See below for a comparison of all the three species 

 of Ginkgoites known to occur in the English Wealden and formally 

 described here for the first time. Comparisons with similar species in 

 Lower Cretaceous floras from elsewhere are also made. 



Ginkgoites garlickianus sp. nov. Figs 16-19 



1 976 26 Gink Gi A Oldham (Code used instead of Linnean bino- 

 mial): 460; pi. 69, figs 1-6. 



Diagnosis, [based on leaf fragments only; leaf probably deeply 

 divided and petiolate] Ultimate lobes up to 3 mm wide and at least 4 

 min long [apices unknown]. Stomata scattered on both leaf surfaces, 

 cuticle 6 pm thick. Stomatal apparatus more or less round to ellipti- 

 cal; guard cells with thickly cutinized semi-circular dorsal plates and 

 inner anticlinal walls, polar areas thinner; sunken beneath ring of 4- 

 7, usually 5, thickly cutinized subsidiary cells forming stomatal pit. 

 Ordinary epidermal cells less thickly cutinized than subsidiary cells, 

 polygonal, mainly 4-sided; anticlinal walls straight. 



Stomata of upper surface about 41 per mm^, avoiding vein tracts; 

 stomatal apparatus 69 (57-8 1 ) pm long and 57 (44-77) |jm wide; pit 

 oval or slit-like; aperture usually longitudinally orientated. Subsidi- 

 ary cells have a hollow papilla overhanging guard cells. Ordinary 

 epidermal cells isodiametric or longitudinally elongate, averaging 

 44 (20-78) |jm long and 20 (10-37) pm wide; some cells; at segment 

 margins with flat outer surface. Most cells with more than one 

 papilla or trichome, up to 50 pm long, many papillae joining to give 

 ridge-like thickenings to surface. 



Stomata of lower surface 83 (58-93) per mm^; stomatal apparatus 

 65 (40-108) |im long and 58 (37-108) pm wide; pit round or square, 

 subsidiary cells sometimes possessing small papillae which over- 

 hang pit; apertures randomly or longitudinally orientated. Ordinary 

 epidermal cells averaging 31 (10-54) pm long and 28 (10-54) \im 

 wide, isodiametric or longitudinally elongate at segment margins 

 where they are arranged in longitudinal files; outer surface flat, 

 lacking thickenings and papillae. 



Name. After Magrat Garlick, witch and Queen of Lancre in the 

 Discworld novels of Terry Fratchett. 



Holotype and type locality. V.64548, Fig. 16A, a dispersed 

 leaf fragment from the 'Grange Chine Black Band" plant debris bed 

 at Grange Chine on the South West coast of the Isle of Wight 

 (Locality LI 1 of Stewart 1978). Wessex Formation; Barremian. 



Material and occurrence. All the specimens of Ginkgoites 



