The Occurrence of Geopora arenosa in the British Isles

Abstract

Summary. The occurrence of Geopora arenosa in the British Isles is confirmed by examination of two British collections from Scotland and comparison with type material of the species. The British record of this name is discussed and a revised key to the known British species of Geopora provided. Peziza arenosa Fuckel (the basionym of G. arenosa) is lectotypified to stabilise the concept of the species. Ascospore drawings from relevant collections are provided to facilitate recognition of British species of Geopora. Five species of Geopora Harkn. were recognised from Britain by Yao & Spooner (1996a) who also discussed all other names in the genus reported from Great Britain and Ireland. Whilst that paper was in press, a new collection was received at Kew which confirmed the presence in Britain of G. sepulta (Fr.) Korf. & Burds. This was reported by Yao & Spooner (1996b), with a key to the six British species then known. Based on examination of Fries's type material, the species concept of G. sepulta held by British authors (Cooke 1876; Phillips 1887; Massee 1895) was shown to be incorrect, and to represent a species with smaller spores (Yao & Spooner 1996a). Previous British records of G. sepulta were considered doubtful (Yao & Spooner 1996b) until the recent collection confirmed its presence here. Further collections of this species are now known from Britain. A similar situation applies to Geopora arenosa (Fuckel) S. Ahmad. Apparently, this was first recorded as British under the name Sepultaria arenosa (Fuckel) Boud. sensu Seaver by Dennis (1960); this was repeated in subsequent editions of his book (Dennis 1968, 1978). Cannon et al. (1985) list this taxon under Geopora without further reference, but probably on the basis of Dennis' work. It was not accepted as British by Yao & Spooner (1996a, b), because the species concept presented by Seaver (1928) and Dennis (1960, 1968, 1978) apparently differs from that represented by the type material. The spore size was given as 23.0 - 25.0 x 13.0 18.0 pm by Seaver (1928) and as 20.0 - 25.0 x 10.0 - 14.0 pm by Dennis (1960, 1968, 1978), considerably different from that of the type material (27.0 - 30.5 x 13.5 15.0 pm; Yao & Spooner 1996a). However, two recent collections from Scotland display similar spore size and fruiting season to those of the type and are here considered as evidence for the occurrence of G. arenosa in the British Isles. A description based on these collections is given below together with a revised key to the hitherto known British species of Geopora. The type material of Peziza arenosa Fuckel preserved in K has been examined and a lectotype is here selected for the