Note on the typification of the moss Calymperes graeffeanum Müll.Hal. and the synonym representing its most westerly occurrence

Carl Müller of Halle (1874) reported on some mosses collected in the Pacific Islands (including Samoa) between 1862 and 1873 by Dr E. O. Graeffe. From among these specimens he described several new species, some of which were named in honour of the collector; these included Calymperes graeffeanum Müll.Hal. Unfortunately, Müller’s herbarium, containing the primary set of the original material (holotypes) on which his new species were based, was largely destroyed in Berlin (B) during the Second World War. However, duplicate specimens of at least some of Müller’s original material had been distributed to several of his contemporaries and now reside in various herbaria in Europe and North America. In the absence of original material in Müller’s own herbarium, necessary typification of his new species must be resolved from among these extant duplicates (Turland et al. 2018, Arts 9.3 and 9.12). The typification of C. graeffeanum requires such resolution. Calymperes campylopodioides Müll.Hal. ex Besch. was described from Cameroon (Bescherelle 1895). Although sometimes confused with C. palisotii Schwägr., it is conspecific with C. graeffeanum (Ellis 2001) and represents a rare African occurrence of the latter. Since it was placed in synonymy with C. graeffeanum (Ellis 2001), original material of C. campylopodioides has come to light, which requires the entity to be more precisely typified. This nineteenth-century record of C. graeffeanum constitutes its most westerly occurrence, and a further, and more recent record from Cameroon (Thompson & Rawlins 1630, MO), collected in 1984, confirms its persistence then, in West Africa. The West African occurrence of C. graeffeanum is disjunct from its otherwise largely Indo-Pacific distribution range; the closest occurrence of the species eastward from Cameroon is a single record from Tanzania, reported by Orbán (1995). Records of C. graeffeanum becomemore frequent eastwards from the islands of the Indian Ocean and through southern India and Malesia; the range of the species extends further eastwards across the Pacific islands, as far as Pitcairn Island (Ellis 1988). Calymperes graeffeanum has been reported as far north as southeastern China (Reese and Lin 1991; Lin and Reese 2001), and its most southerly occurrence is in tropical Australia (Ellis 1988; Reese and Stone 1995).