REVISION OF THE ENGLISH WEALDEN FLORA 



79 





Fig. 39 Torreyites detriti sp. nov. From Wessex Formation, Isle of Wight. Inside of lower cuticle showing stomata scattered within longitudinal groove, 

 SEM,V.64613. x200. 



Fig. 40 Torreyites detriti sp. nov. From Wessex Formation, Isle of Wight. One stomatal groove showing distribution of stomata and orientation of slit-like 

 stomatal openings, V.646 13, x 200. 



that this species was also deciduous. Examples of fossil populations 

 representing mass leaf drops (brachyblasts) have been noted as a 

 widespread phenomenon in Phoenicopsis, Czekanowskia and 

 Spheuobaiera by Vakhrameev (1991). PseitdotorelUa linkii occurs 

 in a similar type of deposit in Dunker's 'Abietites leaf coal' in the 

 Wealden of Germany, though such concentrations have not been 

 recognized in the English Wealden. Bose & Manum (1990, 1991) 

 have also described needle-leaved conifers of the PseudotoreUial 

 Sciadopityoides-type in pure leaf coals together with Siilcatocladits- 

 type shoots (see discussion above). Clearly, all these occurrences of 

 ginkgoalean, czekanowskialean and coniferalean brachyblasts indi- 

 cate deciduousness, which itself indicates seasonality of some kind. 

 This scenario of mixed gymnospemi forests in moister valleys is 

 not inconsistent with the current consensus view of the climate of the 

 Wealden, as drawn from a wide range of disciplines by Allen (1998). 

 He describes a very warm, seasonal 'Mediterranean' climate with 

 occasional equable humid periods and generally wetter conditions 

 on the upland massifs than in the plains. However, the presence of the 

 species described here suggests that localized upland areas may have 



remained moist for sustained periods, allowing the development of 

 mixed forest groves. It is hoped that further studies of plant debris 

 material will continue to improve our understanding of Wealden 

 palaeoecology and climate. 



Acknowledgements. We are most grateful to those who provided us 

 with debris material which yielded the plants in this paper: Karl Gray who 

 originally isolated Torreyites leaves; Steve Hutt for the Grange Chine Black 

 Band material; Mick and Male Green for field guidance; Helen Cusack Drury, 

 Michael Henderson and David Batten forextensive help with collecting. Lucy 

 Thompson, Kate Lloyd Bostock. Peta Hayes and Peter Spark gave invaluable 

 assistance with sieving, sorting and SEM of countless buckets of debris. We 

 especially wish to thank Tiffany Foster (now Tiffany Adrain) formerly of the 

 NHM for helping us in so many ways. 



Nicola Harrison held a NERC Research Studentship, and Susannah Lydon 

 a Manchester University Research Scholarship, whilst undertaking this study; 

 Joan Watson was supported by a NERC Research Grant for field work, which 

 they gratefully acknowledge. The preparation of this paper was funded by a 

 NERC Taxonomic Publications Grant awarded by The Linnean Society of 

 London. 



