Bulletin of the British Museum (Natural History)

202 BRIAN JOHN COPPINS
0-1-0-2 mm diam. Areolae often disintegrating to form a scurfy-granular crust. Phycobiont not micareoid;
cells in clusters and tightly bound by short-celled hyphae, but haustoria not observed; clusters interconnected
by filamentous hyphae c. 1-5-2 ju.m wide. Phycobiont cells irregularly globose, broadly ellipsoid or
oblong, c. 5-12(-18)x3-8 />tm, often arranged in pairs or in short chains of up to four cells (Figs. 57C).
Apothecia convex-hemispherical and immarginate from the beginning, sometimes becoming subglo-
bose, more rarely tuberculate, grey-black with bluish tinge, but shade forms sometimes whitish, blue-grey
or grey-brown, 0-l-0-3(-0-4) mm diam; base of apothecia with a white rim (c. 50 /xm wide) of outwardly
radiating hyphae. Hymenium 28-35 /xm tall, dilute straw (shade forms), or dilute greenish or aeruginose
(K-l- green intensifying) especially in the upper part. Asci cylindrical-clavate, 25-30x5-7 /im, 8-spored.
Spores ovoid, oblong-ovoid or dacryoid, simple, 3-6x(l-)l-2-l-7(-2) /xm (Fig. 57A). Paraphyses (Fig.
57B) numerous, usually branched, sometimes anastomosing, distinctly septate and appearing ± articu-
lated, stout, 1-3-2 /Ltm wide; apices sometimes ± clavate and up to 3 jxm wide, walls not pigmented but
often surrounded by deeply pigmented gel matrix. Hypothecium c. 50-70 /tim tall, hyaline, or dilute
greenish or aeruginose (K— , HNO3-I- red) but then never darker than the hymenium. Excipulum
indistinct, of radiating hyphae that protrude as loose, hyaline hyphae c. 1-5-2 /xm wide and up to 50 /x,m
long.
Pycnidia not found.
Chemistry: All parts K- , KC- , C- , PD- ; no substances detected by t.l.c.
Preliminary studies of Lecidea clavulifera by Mr P. W. James and myself led us to transfer it to Micarea.
However, critical studies have given me second thoughts on this placement. The distinct white rim of
protruding excipular hyphae (superficially like those of Byssoloma spp.), stout and distinctly septate
paraphyses, and the unusual phycobiont are all uncharacteristic of a Micarea. The consideration of
Psilolechia Massal. as an alternative genus for L. clavulifera was prompted by observations of a
lichenicolous member of the CaHciales, Microcalicium arenarium (Hampe ex Massal.) Tibell; M. arenarium
is usually found as a parasite of Psilolechia lucida (Ach.) M. Choisy (see Tibell, 1978), but at three
localities in Scotland I have found it on L. clavulifera. At the Berwickshire locality the host and parasite
occurred in abundance on roots, stones, and soil of two up-ended trees (Fraxinus); P. lucida was also
present in quantity but was not parasitized by M. arenarium.
With the exception of pigmentation, sections of the ascocarps of P. lucida and L. clavulifera show ±
identical anatomical features, e.g. nature of paraphyses, size and shape of asci and spores, and excipulum
with numerous protruding hyphae. P. lucida differs from P. clavulifera in the yellow-green colour of its
leprose-granular thallus and apothecia (due to presence of pulvinic acid derivatives), and a different
phycobiont with ± globose cells 5-14 /xm diam. The thallus hyphae of both species are identical in
appearance, and pycnidia are not known in either species. A recent account of P. lucida is given by James
(in Poelt & Vezda, 1981). The phycobiont of P. clavulifera is very unusual; it is reminiscent of the
Stichococcus phycobiont of species such as Chaenotheca stemonea and Coniocybe furfuracea, but its cells
are much larger.
P. clavulifera occurs in communities of the Micareetum sylvicolae, on roots, stones, and consolidated soil
of underhangs on banks or the root systems of up-ended trees. Most British records are from Scotland, but
it is also known from Cumbria, south Wales and western Ireland (Map 28). From outside Britain I have
seen material of it from Finland, Germany, and Czechoslovakia (see below).
Additional specimens of P. clavulifera examined: British Isles. Brecon (V.C.42). 22/94: Upper
Dyfnant Valley, 1982, Woods (hb Woods). Cumberland (V.C.70). 35/54: Baron Wood, by River Eden,
60-75 m dry sandstone cliff, 1979, Coppins 4344 (E). Berwick (V.C.81). 36/76: W of Elba, S side of
Whiteadder Water, exposed roots of up-ended Fraxinus, 1981, Coppins 8890 (E - Microcalicium
arenarium folder). West Perth (V.C.87). 27/40: Aberfoyle, the Trossachs, on stone amongst roots of
up-ended tree, 1978, Coppins3661 (E). Mid Perth (V.C. 88). 27/55: Black Wood of Rannoch, stone in bank
by track, 1976, Coppins 4654 (E); 27/81: Crieff, Drummond Wood, roots and sandstone of up-ended tree,
partly parasited by Microcalicium arenarium, 1978, Coppins 3164, 3625 (E). Angus (V.C. 90). 37/33:
Sidlaw Hills, Auchterhouse Hill, 396 m, underside of boulder, 1975, Coppins 846 (E - Microcalicium
arenarium folder). South Ebudes (V.C. 102). 16/49: Colonsay, Coille Mhor, roots and soil of up-ended
Betula, 1981, Coppins 8878 (E). Mid Ebudes (V.C. 103). Mull: 17/32: Bunessan, Ardfenaig Woods, 1970,
James (BM); 17/54: Salen, 1968, James (BM); 17/55; Aros House, roots of up-ended tree, 1968, James
(BM). West Galway (V.C.H.16). 84/72 (L/65): Connemara, near Clifden, 1878, Larbalestier (BM).
Finland. Satakunta: Siikainen, Vuorijarvi, Vaasaneva, sandy soil amongst roots of Picea, 1936, Laurila
(GZU, H). W. Germany. Baden-Wiirttemberg: Heidelberg, Konigstuhle, on sandstone, 1883, Zwackh
(H-NYL p.m. 4229). Czechoslovakia. Slovakia, Nizke Tatry, Liptovska Teplicka, Dzurova, 18 -, Lojka
4289 (BM).