Some Pennsylvanian arborescent lycopsid cones and their microspores from the British coalfields

Abstract

Six fructifications of arborescent lycopsids and their in situ spores from the Westphalian Coal Measures of the Pennine Basin and the Clackmannan Coalfield in Scotland, UK, were studied to improve our knowledge of their taxonomic characteristics and to provide a basis for the comparison of the floras of the British and Czech coalfields. The cones, which yielded in situ spores, were assigned to the genera Lepidostrobus (Brongniart) Brack-Hanes & Thomas, Flemingites (Carruthers) Brack-Hanes & Thomas and Sigillariostrobus Schimper. Lepidostrobus cones are represented by four species/specimens that can be subdivided into two groups based on their in situ spores. L. boltonensis n. sp., L. huttonii n. sp. and L. spinosus Kidston contain cingulizonate lycospores with relatively narrow cingulum and narrow zona which are comparable with the dispersed species Lycospora subjuga Bharadwaj, L. brevijuga Kosanke, L. triangulata Bharadwaj, L. microgranulata Bharadwaj or L. contacta Habib. The cone L. cf. obovatus yielded in situ lycospores with narrow cingulum and wide zona similar to those of the dispersed species Lycospora loganii (Wilson) Potonié & Kremp, L. pellucida (Wicher) Schopf, Wilson & Bentall, L. micropapillata (Wilson & Coe) Schopf, Wilson & Bentall, L. micrograna Hacquebard & Barss, L. intermedia (Wilson & Hoffmeister) Wilson & Hoffmeister, L. pseudoannulata Kosanke and L. perforata Bharadwaj & Venkatachala. The genus Flemingites is represented by F. cf. russelianus Binney. The Flemingites cone yields in situ microspores identified as the Lycospora orbicula-type. Sigillarian cones are rare and were represented by a single specimen of Sigillariostrobus acicularis n. sp. which contained Crassispora kosankei-type microspores. Only one of these British species (Lepidodendron cf. obovatus) is unequivocally present in the coalfields of central and western Bohemia. It is probable that Flemingites cf. russelianus also occurs in both areas.