A Synopsis of the Genera Skyttea, Llimoniella and - Lichens of ...

424 THE LICHENOLOGIST Vol. 32
beginning was heterogeneous (as already noted by Sherwood et al. 1981),
became more and more an assemblage of non-related species.
Zhuang (1988: 62) was the first to recognize that Skyttea included a
leotialean species, and she consequently transferred 5. thallophila to
Unguiculariopsis, a genus with mainly fungicolous (inch lichenicolous) taxa.
Later Coppins (in Rambold & Triebel 1990: 386-387) combined two other
species, 5. lettaui and 5. refractiva into Unguiculariopsis, a genus which we
know to comprise at least 10 lichenicolous species.
The genus Skyttea was originally said to be related to Odontotrema
(Sherwood et al. 1981), a genus with lignicolous species. Later, Hawksworth
& Sherwood (1982) described the new family Odontotremataceae (Ostropales)
to include Odontotrema, Skyttea and five other genera. A more general
overview of the Odontotremataceae, together with keys and descriptions of the
accepted genera, is provided by Sherwood-Pike (1987).
Triebel (1989: 142-147) proposed to treat Skyttea in a broad sense as a
recent synonym of Rhymbocarpus, and combined three known species of
Skyttea into that genus. Coppins et al. (1991: 51) showed, however, that the
type species of Rhymbocarpus has a very different ascus type and a different
excipular structure, and suggested that the monotypic genus Rhymbocarpus
should be best considered as Hncertae sedis pending the availability of fresh
material'.
The aim of this paper, initially, is to give a new circumscription of a
homogeneous genus Skyttea, to discuss its systematic position, to transfer all
excluded species to other genera, to study and solve some taxonomic problems
concerning those genera, and to describe several new taxa. We did not plan a
complete revision of the genus, and some well-known species presenting
no taxonomic problems, and of which a modern published treatment is
available, were not studied in detail. While preparing this synopsis, we
examined a large number of other leotialean lichenicolous fungi, and we
realised that a completely new arrangement of the taxa previously included in
Llimoniella should be proposed, including the recognition of an enlarged genus
Rhymbocarpus. As a consequence, we also prepared synopses of Llimoniella and
Rhymbocarpus. Some species formerly included in Skyttea or Llimoniella are
excluded and are treated as species of the genus Unguiculariopsis.
Materials and Methods
The specimens examined are located in the institutional herbaria ASU, BG, BM, CBG, E, FH,
G, GZU, H, HBG, IMI, LE, LG, LUX, M, MA, MARSSJ, NY, TRH, UC, UPS and VAB, or
in the personal collections of J. Alvarez, A. Aptroot, P. van den Boom, P. Diederich, J. Etayo, K.
Kalb, V. Kummer and H. T. Lumbsch. In the enumeration of specimens, the abbreviation (h)
means the private herbarium of the collector. In the case of several collectors, only the first, or the
owner of the specimen is cited.
The morphological characters (dimensions, colour, fissures, etc.) of dry herbarium specimens
have been studied and illustrated with a dissecting microscope at a magnification of x 40 or x 80.
Microscopical examinations (including all microscopical measurements) were carried out using
hand-cut sections in water; semi-permanent preparations of some species have been prepared in
lactophenol cotton blue (LCB). As almost all the herbarium specimens are at least five years old,
descriptions and measurements are normally based on dead cells. The excipular pigments have
been studied in water, in 5-10% KOH (K) and in concentrated nitric acid (N); the dark red