(1596-1597) Proposals to conserve the name Anthoceros with a conserved type and the name Anthoceros agrestis against A. nagasakiensis (Anthocerotophyta)

When Linnaeus (Sp. PI.: 1139. 1753) named the genus Anthoceros he included three species, namely, A. punctatus, A. laevis, and A. multifidus. Anthoceros multifidus was later removed from the genus and transferred to Riccardia by Gray (Nat. Arr. Brit. PI.: 684. 1821 'Riccardius') leaving two of the original species in the genus Anthoceros. Anthoceros punctatus was selected as the generitype by Proskauer (Ann. Bot., n.s. 12: 259. 1948). His selection remained uncontested until Schuster (J. Hattori Bot. Lab. 26: 299. 1963) suggested that Proskauer should have selected A. laevis as the type rather than A. punctatus. That is because Proskauer later decided (Bull. Torrey Bot. Club 78: 346, 1951) that these two original species of Anthoceros actually represented two different genera. Since he had selected A. punctatus as the type, it had to remain with Anthoceros, so he transferred A. laevis to his new genus Phaeoceros (Proskauer I.c., 1951). Anthoceros punctatus had long been considered to be conspecific with Aspiromitus husnotii Steph., the generitype of Aspiromitus Steph. (Proskauer, I.c., 1948: 262), and Schuster (I.c., 1963) stated that "Aspiromitus, typified by A. husnotii (= A. punctatus) must be used for one of the two elements originally included in Anthoceros by Linnaeus, and Anthoceros must be retained for the other ('law of residues')". Following his logic, the two species of Linnaeus would then be Anthoceros laevis and Aspiromitus punctatus; he did not, however, make any new combinations in 1963. Schljakov (Novosti Sist. Niz. Rast. 13: 225. 1976) agreed with Schuster (I.c., 1963) and implicitly lectotypified Anthoceros with Anthoceros laevis, making the new combination Aspiromitus punctatus (L.) Schljak. Grolle (Acta Bot. Fenn. 121: 5. 1983) pointed out that such a later lectotypification was contrary to the provisions of the ICBN, particularly with the removal of any appeal to the "law of residues" in the edition adopted at the Sydney Congress of 1981 (Voss & al., Regnum Veg. 111. 1983) and had to be rejected. That would have been the case except for the provision of the ICBN, first adopted at the Seattle Congress in 1969 (cf. Art. 8 (last clause) in Stafleu & al., Regnum Veg. 82. 1972), and now expressed as Article 10.5(b) of the ICBN (Greuter & al., Regnum Veg. 138. 2000) that a choice of lectotype for the name of a genus or subdivision of a genus may be superseded if ". . . it was based on a largely mechanical method of selection". The selection by Proskauer (l.c., 1948: 262) was obviously mechanical since he wrote: "Anthoceros punctatus was described by Linne (1753) as the first species of Anthoceros. It is here, therefore, considered as the type of the genus". Although the actions of Schuster (l.c., 1963) and Schljakov (l.c.) do not represent formal designation of a type as required by Art. 7.11 of the ICBN, more recently Schuster (Hepaticae and Anthocerotae of North America 6: 745. 1992), following his description of Anthoceros, wrote: "Type. Anthoceros laevis L. The reasons for the present type designation are discussed at length, below". Although this later designation was based solely upon the "law of residues" with no mention whatsoever of the mechanical choice by Proskauer (l.c. 1948: 262), Art. 10 Ex. 7, a "voted example", makes clear that any later type designation that meets the requirements of Art. 7.11 supersedes a choice "based on a largely mechanical method of selections". Therefore, unless the Proskauer designation of A. punctatus is conserved as the type of the name Anthoceros, it must be considered to have been superseded by Schuster's (I.c. 1992: 745) choice of A. laevis. With A. laevis as the generitype, the species of Phaeoceros must either be returned to or transferred to Anthoceros and all species now considered to be members of Anthoceros must be transferred to Aspiromitus. Schuster (l.c., 1992) and Schljakov (l.c.) have already begun this lengthy task to a very limited extent. Not only will the number of new combinations be high, including well over 100 of the 293 binomials listed by Bonner (in Index Hepat. 2. 1962) under Anthoceros, the confusion this will cause will be unprecedented. This will likewise result in changing the generic name for 131 sequences