Nomenclatural Problems in Crum and Anderson's Mosses of Eastern North America and an Evaluating Dream

Abstract

During the Sydney Congress I was able to acquire a copy of the magnificent book of H. Crum and L. E. Anderson: Mosses of Eastern North America, published earlier this year. At home, one of my first jobs was to compare its nomenclature with that of the Index Muscorum in connection with the preparation of the Supplement, 1963-73. Of course I looked for an answer to the problem I twice pointed out to Dr. Crum, in 1969 and in 1973. He had followed a general idea expressed in a paper by Dixon (1934), apparently not knowing that Dixon changed his mind (1939) after a talk with Dr. Sprague. Dixon (1934) used a saying once a synonym, always a in a broad sense, applying it to an epithet in whatever combination it appeared. This, as Dr. Sprague pointed out to Dixon, is not the case: only the name in question is illegitimate and the epithet can be used in any other combination (International Code of Botanical Nomenclature, I.C.B.N., Leningrad version, 1978, Art. 72.1). A simple example of this case is the name Isothecium stoloniferum Brid. 1827, based on Hypnum stoloniferum Hooker 1818, an illegitimate name being a later homonym (I.C.B.N., Art. 64.1). Crum et al. (1965 [1966]), interpreting the Isothecium name to be also illegitimate, chose the later name Isothecium spiculiferum as the correct name instead. Another name, connected with this case, is Isothecium myosuroides Brid. 1827. After the change of the starting-point from Linnaeus to Hedwig, this name seemed in danger, since Bridel explicitly excluded the name Hypnum myosuroides Hedw. from his circumscription and based his new name on Hypnum myosuroides L. instead. Dixon (1934) thought that Bridel's name was illegitimate and created a new epithet: Isothecium eumyosuroides. I agree with Dr. Sprague and Dixon in his later publication (1939) that Bridel was perfectly free (according to the present Code) to use this combination. In accord with the Linnaean starting-point he was compelled to do so, but we leave this out of consideration. Nevertheless, during preparation of the Index Muscorum, I carefully checked if there might be another reason for the possible illegitimacy of Bridel's name because of the infamous article on superfluous names (I.C.B.N., Art. 63.1); this possibility had not been checked by Dr. Sprague or Dixon, as far as I know. I did not find any objection. Apart from a number of invalid pre-Hedwigian names, Bridel cited Hypnum curvatum Schumacher 1803, doing this, apparently, in a way excluding its type-bringing synonym of Swartz, validated by Dickson 1801, since Bridel cited Hypnum curvatum Swartz in the synonymy of his Hypnum myosurum Schrader, validated by Giirtner, Meyer & Scherbius in 1803. However, this name is a later homonym of Hypnum myusuron With. 1801, itself a superfluous name for H. myosuroides Hedw. So I cannot escape the conclusion that the name Isothecium myosuroides Brid. is perfectly legitimate; thus the name I. eu-myosuroides Dixon is illegitimate. The connection between these names is that they often are considered to be conspecific. I was aware of this problem when compiling the Index Muscorum, although they finally were kept apart. The obvious place to look for an early person to lump such species