Sorbus foliolosa (Wallich, 1831) Spach, 1834

Chen, Xin, 2018, Taxonomic and nomenclatural notes on Sorbus foliolosa and related taxa (Rosaceae), Phytotaxa 382 (3), pp. 297-300 : 297-298

Sorbus foliolosa and S. wallichii

Sorbus foliolosa was originally described as Pyrus foliolosa Wallich (1831: 81) , which was firstly listed as a nomen nudum in the Catalogue of Wallich (1828: 20) referring to “677 Pyrus foliolosa, Wall. in Herb. 1824. Napalia 1821”. However, Wallich 677 includes specimens collected from two localities, Gossain Than and Sheopore in Nepal. Thus, it comprises two different gatherings according to the Art. 8.2 footnote 2 ( Turland et al. 2018).

Hooker (1878) noticed that the two gatherings represent two different taxa and the original description of Pyrus foliolosa is a mixture. He actually lectotypified Pyrus foliolosa Wallich by restricting P. foliolosa to material collected from Gossain Than (lectotype!) with 9–11 pairs of leaflets and rusty brown hairs on abaxial side of leaflet, petiole and inflorescence, and cited P. ursina Don (1832: 648) as its synonym. He described the specimens from Sheopore (the remaining syntypes) as a new species, P. wallichii Hooker (1878: 376) , which differs from P. foliolosa in having 7–8 pairs of leaflets and white wool on abaxial side of leaflet, petiole and inflorescence.

Hooker’s treatment was followed by Long (1987a, b) and McAllister (2005). Yü (1974) transferred Pyrus wallichii to the genus Sorbus as S. wallichii . However, the description provided by Yü for the species was inconsequently with “leaflets 4–6 (–9) pairs” as Hooker’s P. wallichii , hairs “rusty brown” as Hooker’s P. foliolosa . Contrary to Hooker’s treatment, Hedlund (1901) illegitimately designated the specimens from Sheopore as lectotype by treating them as S. foliolosa and the specimens from Gossain Than as S. ursina , and reduced P. wallichii to a synonym of S. foliolosa . Hedlund’s treatment was followed by Gabrielian (1978) and Lu & Spongberg (2003). But, the description of S. foliolosa provided by Lu & Spongberg was just as ambiguous as the description of S. wallichii provided by Yü. The different circumscriptions of P. foliolosa and P. wallichii by Hooker and Hedlund caused great confusion. Therefore, nomenclatural types for the two names need to be clarified to avoid future confusion.

Eight specimens of Wallich 677 were traced at E, K, GZU, LE, M and P. Two specimens, K-001111574 and M-0213764 (the upper and right parts) collected at Gossain Than, belong to one gathering. While six specimens, K-001111573, E-00010894, GUZ-000283011, LE-00013475, M-0213764 (the left part) and P-02143308 collected at Sheopore, belong to another gathering. Hooker (1878) correctly separated Wallich 677 into two species, and his designation of the lectotype of P. foliolosa is effective. Gabrielian (1978) cited the type of P. foliolosa as “Typus: Nepalia, 1821, Wallich Cat. 677 (K-W)”, which was not accurate because there are two gatherings under Wallich 677 in Wallich’s herbarium. Long (1987a) labeled one specimen from Gossain Than at K-W (K-001111574) as 677a, another one from Sheopore (K-001111573) as 677b, and cited them as the lectotype of S. foliolosa and S. wallichii , respectively. Long’s citation of K-001111574 as the lectotype of S. foliolosa is actually the second-step lectotypification of the name. His designation of the lectotype of S. wallichii is effective. Based on the taxonomic analysis, it is proposed to recognize S. foliolosa and S. wallichii as two species.