Fróðskaparrit - 01.01.1992, Page 82

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THE LICHENS OF THE FAROES
omnino immersa vel regionibus ostilaribus
protrudentibus. Excipulum circiter 20 pm
crassum, ex cellulis isodiametricis vel
secundum superficiem elongatis, 2-4 x 3-6
pm magnis compositum, in parte libera
viridulum, in partibus immersis pallide
viridulum vel colore nullo. Asci cylindrici,
circiter 80-100 x 7.5-8.5 pm magni,
octospori. Ascosporae ellipsoides, septo
unico divisae, cellula superiore inferiorum
diametro superante, hyalinae, 13-16 x 4.5-
5.5 |im magnae.
Lichenicolous pyrenomycete. Ascomata
up to c. 100 pm diam., immersed in the host
thallus or with protruding ostiolar region.
Excipulum c. 20 pm thick, composed of
isodiametric or tangentially elongated cells
2-4 x 3-6 pm, free parts greenish, immersed
parts pale greenish to uncoloured. Asci
cylindrical, c. 80-100 x 7.5-8.5 pm, 8-
spored. Ascospores ellipsoid, 1-septate, the
lower cell narrower than the upper one,
hyaline, 13-16 x 4.5-5.5 pm.
Holotype: Faroe Islands, Streymoy,
Somfelli, alt. c. 700 m, on Arthroraphis
alpina (Schaerer) R. Sant., 7 June 1985,
Alstmp 85868 (C).
The new species will key out close to C.
epipolytropa (Mudd) Amold, which occurs
in the hymenia of the Lecanora polytropa
group. Yet, it has slightly smaller
ascospores and the excipulum is greenish,
not olivaceous tuming greenish with K.
Furthermore, the lichenicolous species of
Cercidospora are normally restricted to one
host or to closely related hosts. The present
species is a weak parasite forming small
cavities in the host thallus, so that old
perithecia are sunken below the surround-
ing lichen thallus. When the perithecia fall
off, the bark of the cavities are of normal
host colour. Even up to 10 perithecia in one
areole does not kill the host.
*Cercidospora epipolytropa (Mudd) Am.
Lichenicolous fungus. On Lecanora po-
lytropa, Somfelli, VA 851427 and
851338; Elduvík, VA 851642;
Slættaratindur, VA 851272. On L. intri-
cata, N of Streymnes, VA 85596,
851338.
*C. cfr. pluriseptata (Nyl.) Zopf.
Lichenicolous fungus. Hestur, SW-
coast, on unidentified cmstose lichen on
rock, VA 8540 lex. The species is
insufficiently known (Keissler 1930
(52), as Metasphaeria pluriseptata) as
the di-agnosis was short. The type spec-
imen (H-NYL) was not available for
loan. The species was not included in
Hafellner’s 1987 treatment of
Cercidospora (49). The Faroese speci-
men has brown excipulum, cylindrical,
thin-walled asci c. 70 x 10 pm surround-
ed by a thin gelatinous sheath. The 8
ascospores are bi-seriate, 3-7-septate,
gelatinous sheath not seen. The 3-septate
ascospores measure 19-22 x 4.5-5 pm,
the 5-7-septate are up to 29 pm long.
They are slightly narrower at the lower
end. The type specimen was found on
Protoparmeliopsis muralis in France.
The Faroese host can well be a Lecanora
s.l., but apothecia are not present.
*C. stereocaulorum (Am.) Hafellner.
Lichenicolous fungus, on Stereocaulon
evolutum, Vágar, Feilberg 1867, with
Scutula stereocaulorum.