REVISION OF THE ENGLISH WEALDEN FLORA 



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Fig. 8 A-H Ginkgoites weatherwaxiae sp. nov. A-F Branched leaf fragments showing up to three successive dichotomies, all x 5. A, V.64534: B, 

 holotype. seen also in Fig. 7C. V.64530: C, V.64535; D, V.64536; E, V.64537: F, V.6453 1 ; G, stomatal distribution and orientation for upper surface, 

 V.64538, X 50; H, stomatal distribution and orientation for lower surface, V.64539, x 50. 



split by at least 3 successive dichotomies at intervals of at least 3.5 

 mm. Ultimate lobes at least 15 mm long, 3 mm wide, of constant 

 width, apices rounded or mucronate. [Veins unknown.] Resin bodies 

 numerous, circular, 50-300 pm in diameter. 



Cuticle 6 |jm thick, stomata present on both leaf surfaces, scat- 

 tered. Stomatal apparatus elliptical in outline; guard cells with 

 thickly cutinized semi-circular dorsal plates and inner anticlinal 

 walls, sunken beneath ring of 4-7, usually 6, thickly cutinized 

 subsidiary cells which surround stomatal pit; pit rim thickened, 

 usually with one hollow papilla per subsidiary cell overhanging 

 guard cells. Ordinary epidermal cells less thickly cutinized than 

 subsidiary cells, polygonal, mainly 4-sided, isodiametric or longitu- 

 dinally elongate, arranged in longitudinal files; anticlinal walls 

 straight, sometimes pitted. Stomata of upper surface averaging 30 

 (13-58) permm^; stomatal apparatus typically 80 (54-1 1 1 ) |jm long 

 and 60 (40-81) pm wide; pit oval or slit like; aperture usually 

 longitudinally orientated. Ordinary epidermal cells averaging 35 

 ( 1 0-67) |jm long and 2 1 ( 1 0^0) pm wide ; outer surface usually flat, 

 very occasionally patches of cells with longitudinal, ridge-like 

 thickenings or small papillae in centre or at end of each cell. 



Stomata of lower surface averaging 64 (42-9 1 ) per mm^; stomatal 

 apparatus typically 70 (40-88) \xm long and 60 (40-78) \xm wide; pit 

 circular to oval; aperture randomly orientated. Ordinary epidermal 

 cells averaging 27 (10-64) pm long and 22 (10^0) [am wide; more 

 longitudinally elongate at margins; outer surface flat, lacking 

 thickenings and papillae. 



Petiole approximately 0.5 mm wide with distinct regions of upper 

 and lower cuticle; when dissected, lower cuticle forming band 0.4 

 mm wide, upper cuticle 1.1 mm wide. Stomata scattered on both 

 surfaces, stomatal apparatus as for lamina. Ordinary epidermal cells 

 of upper surface typically 4-sided. 54 (30-84) \xm long and 14 (7-24) 

 |im wide, arranged in longitudinal files. Stomata 73 (34-105) pm 



long and 51 (34-61) pm wide, longitudinally orientated, averaging 

 1 1 per mm^. Ordinary epidermal cells of lower surface polygonal, 

 mostly 4-sided, 40 (17-67) pm long and 19 (10-34) pm wide, 

 arranged in vague longitudinal files. Stomata 69 (52-81) pm long 

 and 60 (51-74) pm wide, randomly orientated, averaging 31 per 

 mm^. 



Name. After Granny Weatherwax, formidable witch of Lancre in 

 the Discworld novels of Terry Pratchett. 



Holotype and type locality. V.64530, Figs 7C, 8B, a dispersed 

 leaf fragment from the plant debris beds of Worbarrow Bay, Dorset. 

 Wessex Formation; Hauterivian. 



Material and occurrence. All specimens of Ginkgoites 

 weatherwaxiae sp. nov. figured here have been found as dispersed 

 fragments, with good cuticle preservation, within the plant debris 

 beds of the Wessex Formation at Worbarrow Bay. Dorset. This 

 species was also identified by Oldham (1976) in samples from 

 Swanage in Dorset, Brook Chine on the South West coast of the Isle 

 of Wight, and from the Ashdown Beds Formation at Hastings and 

 Galley Hill in East Sussex. Stratigraphical range: Berriasian - 

 Barremian. 



Description and discussion. The fragments of Ginkgoites 

 weatherwaxiae sp. nov. recognised so far indicate the presence of a 

 lamina which is deeply divided into narrow dichotonii/ing segments 

 (Figs7A-D; 8 A-F) and a distinct petiole (Fig. 9A)but it has not yet 

 proved possible to reconstruct a whole leaf. Fig. 7 A, B shows typical 

 terminal segments; Fig. 7C, D and Fig. 8A-F show branching of 

 primary lobes into smaller terminal segments. The segment apices 

 vary considerably, being rounded (Fig. 7A), blunt (Fig. 8C). pointed 

 (Figs 7B, 8F) and even forked (Fig. 7D). The pointed type of apex, 

 such as that of the specimen in Fig. 7B. F is sometimes mucronate 



