A CONSPECTUS OF THE LICHEN GENUS STEREOCAULON ...

192 Journ. Hattori Bot. Lab. No. 43 1977
or intermixtures of other species may be present. We have mentioned such cases in
our listing when they were detected in the limited number of sets examined.
Stereocaulon belongs to the class Ascomycetes, subclass Ascomycetidae, order
Lecanorales, family Stereocaulaceae, which also includes the genera Argopsis, Compsocladium
and Pilophorus (HENSSEN and JAHNS, 1974; POELT in AHMADJIAN and HALE,
1973). According to COOKE and HAWKSWORTH (1970) the first valid publication of the
family Stereocaulaceae was by CHEVALLIER, 1826-27, as an "order", with the spelling
"Stereocauleae". The characters of the family are: fruit body an apothecium; ontogeny
gymnocarpic; developmental type ascohymenial; asci unitunicate; true paraphyses
present; erect structure a pseudopodetium; phycobiont of thallus Chlorophyceae;
cephalodia present (HENSSEN and JAHNS, 1974). In Stereocaulon the spores are elongateellipsoid
to cylindrical-fusiform or vermiform, transversely multiseptate (very rarely with
1 or 2 longitudinal septa); in Argopsis muriform or submuriform; in Compsocladium
acicular or filiform, transversely multiseptate; and in Pilophorus simple (unicellular).
The generic epithet Stereocaulon (SCHREB.) HOFFM. (1796) is a conserved name
(LANJOUW et al., Int. Bot. Code, 1966, p. 247)'. It is conserved against Stereocaulon
SCHRAD. (1794), which was based on Lichen corallinus L.,=Pertusaria corallina (L.)
ARN., and also against Coralloides HOFFM. (1790, non WOLF, 17763), which was based on
Lichen paschalis L. (also the type species of Stereocaulon HOFFM.). Leprocat~lon NYL.,
which has commonly been included in Stereocaulon, is a distinct and unrelated genus;
see LAMB and WARD, 1974.
The first published monographic treatment of the genus was by TH. FRIES (1857,
1858). Prior to that date at least two monographic studies appear to have existed in
manuscript, by DELISE and by LAURER; references are found in the early literature and
on old herbarium labels to "Delise Monogr. ined." and "Laur. Monogr. ined." Later
published studies, with the exception of those of DODGE (1929) and LAMB (1951), have
been mostly regional, the most important being by MAGNUSSON (1926), FREY (1932),
KERSHAW (1960), POELT (1969), DAHL and KROG (1973) for the European species,
RIDDLE (1910) for the North American species, and YOSHIMURA (1974) for the Japanese
species. A study of the pseudopodetial and apothecial ontogeny in several species of
Stereocaulon was made by JAHNS (1970), who confirmed the validity of the criteria
on which the subgenera Enteropodium (= Stereocaulon) and Holostelidium LAMB (1951)
The first usage of the epithet Stereocaulon was by SCHREBER (1791), as Lichen sect. Stereocaulon.
He did not mention any species, but it is probable that he included in the section species of both Stereocaulon
and Pertusaria. On account of the fact that SCHREBER did not mention any type species, the
question of subsequent typification of the genus arises. The first typification was that of SCHRADER,
1794, on Lichen corallinus L. (=Pertusaria corallina (L.) ARN.), but this is now rejected. HOFFMANN,
1796, included several species, including St. paschale (L.) HOFFM., in Stereocaulon, without citing any
particular one of them as the type species. As far as we have been able to ascertain, the first lectotypification
of the genus on St. paschale (L.) HOFFM. was by CLEMENTS and SHEAR on p. 320 of "The
Genera of Fungi" (1931), where the genus is written "Stereocaulurn", and this lectotypification is approved
by the entry in the International Code (LANJOUW et al., 1966).
The lectotype of Coralloides WOLF (1776) is Lichen subulatus L. (=CIadonia subulata (L.) WIGG.);
see Ross, 1966.