Corylus heterophylla Fisch.

Holstein, Norbert, Tamer, Sarah el & Weigend, Maximilian, 2018, The nutty world of hazel names - a critical taxonomic checklist of the genus Corylus (Betulaceae), European Journal of Taxonomy 409, pp. 1-45 : 23

10. Corylus heterophylla Fisch. ex. Trautv.

Plantarum Imagines et Descriptiones Floram Russicam Illustrantes 1: 10, fig. 4 ( Trautvetter 1844). – C. tetraphylla Fisch. ex Ledeb., Denkschriften der Königlich-Baierischen Botanischen Gesellschaft in Regensburg 3 (2): 58 ( Ledebour 1841) nom. nud. (sphalm. for C. heterophylla Fisch. ). – C. avellana var. davurica Ledeb., Flora Rossica 3 (2): 588 ( Ledebour 1850) [“ 1850–1851 ”]. – Original citation: “Delineavi ad specimina Argunensia sicca.” – Type: Russia, ad fl. Argun, s. coll., s.n. (lecto-, designated here: LE 01012787!). – Additional original material: Russia, ad fl. Argun, [comm.? leg.?] 1836, F.E.L. Fischer 5 (BR!, P06810938!); Russia, ad alterum litteri Arguni in Dahuria chinensi, 1820, C.F. von Ledebour s.n. (P06810936!); Russia, Dahuria, ad fl. Argun, N. Turczaninov s.n. (GOET!, P06810932!); Russia, in montosis ad fl. Argun, 1831, s. coll., s.n. (K!, LE 01012790!, MW0049851!); Russia, in montosis Dahuriae ad fl. Argun, 1831, s. coll., s.n. (LE 01012785!, LE 01012788!); China, in Dahuriae Chinensi, ad fl. Argunum, 1830–1831, N. Turczaninov s.n. (LE 01012784!, LE 01012789!). – Note: the specimen designated as lectotype is from Trautvetter’s herbarium, so it is certainly an original. It matches all characters given in the protologue as it is provided with leaves, nuts and young male catkins. The epithet heterophylla was validly published before in Corylus as a variety of C. avellana , but it was used for a cultivar with deeply incised leaves (now ‘Urticifolia’). However, as neither Trautvetter nor Fischer dealt with a cultivar, but with a Siberian wild species, their name is not to be treated as a new combination (Art. 41.4, McNeill et al. 2012). Ledebour cited the protologue of C. heterophylla in total under his new name C. avellana var. davurica . As he included the type of C. heterophylla , his name would be superfluous, but the combination to be adopted was not available due to C. avellana var. heterophylla Loudon (1838) . Therefore, C. avellana var. davurica Ledeb. is to be regarded as a nom. nov.