Bulletin of the British Museum (Natural History)
Bulletin of the British Museum (Natural History)
Bulletin of the British Museum (Natural History)
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LICHEN GENUS MICAREA IN EUROPE 181<br />
James) Vezda and 5". schadeanum (Erichsen) Vezda, but those species have narrower spores<br />
which are spiralled in <strong>the</strong> ascus and non-micareoid phycobionts (? Trebouxia); moreover, S.<br />
pruinosum has a granular epi<strong>the</strong>cium (granules dissolving in K). Fur<strong>the</strong>rmore, <strong>the</strong>se species<br />
have inconspicuous (? unknown) pycnidia, and do not contain gyrophoric acid.<br />
For illustrations <strong>of</strong> conidia and conidiogenous cells, and for fur<strong>the</strong>r discussions, see Coppins<br />
& James (1979).<br />
Habitat and distribution: M. pycnidiophora is a species <strong>of</strong> old woodlands, in damp, sheltered,<br />
and ra<strong>the</strong>r shaded situations. It is generally found on areas <strong>of</strong> ± smooth-bark on <strong>the</strong> boles <strong>of</strong> old<br />
trees, especially Fagus and Ilex, but also Alnus, Quercus, and Rhododendron. Although<br />
characteristic <strong>of</strong> acid bark it has not yet been recorded on conifers.<br />
Its known centre <strong>of</strong> distribution is <strong>the</strong> New Forest <strong>of</strong> Hampshire in sou<strong>the</strong>rn England, where it<br />
is locally frequent. Its o<strong>the</strong>r <strong>British</strong> localities are Sheffield Park in Sussex (on Rhododendron<br />
with Gyalideopsis anastomosans) and <strong>the</strong> Limb Valley, Yorkshire (its most nor<strong>the</strong>rly locality; at<br />
base <strong>of</strong> Fraxinus). The latter site is an ancient oak-wood just outside <strong>the</strong> large industrial city <strong>of</strong><br />
Sheffield, but M. pycnidiophora occurs in an extremely sheltered situation, where it presumably<br />
avoids <strong>the</strong> effects <strong>of</strong> <strong>the</strong> high levels <strong>of</strong> air pollution prevalent in that area. M. pycnidiophora is<br />
little known outside <strong>of</strong> Britain, but is reported from Bretagne, France (Coppins, 1971, as<br />
'Bacidia sp. 2') and <strong>the</strong> Canary Islands.<br />
36. Micarea rhabdogena (Norman) Hedl.<br />
(Fig. 29A)<br />
in Bih. K. svenska VetenskAkad. Handl. Ill, 18 (3): 75, 85 (1892). - Biatora (Lecidea) rhabdogena<br />
Norman in Ofvers. K. VetenskAkad. Fork. 11: 803 (1870). - Lecidea rhabdogena (Norman) Th. Fr.,<br />
Lich. Scand. 2: 473 (1874). Type: Norway, Nordland, Maalselven, Skjeggenaes, J. M. Norman (O -<br />
lectotype!; isolectotypes: BM!, O!, S!).<br />
Lecidea glomerellaf. ecrustacea Nyl. ex Vainio in Acta Soc. Fauna Fl. fenn. 57 (2): 457 (1934). - Lecidea<br />
glomerella f. ecrustacea Nyl. in Elfving in Medd. Soc. Fauna Fl. fenn. 2: 168 (1878); nom. nudum (Art.<br />
32). Type: USSR, Karelskaya ASSR, Karelia olonetsensis, Gorki near Svir, F. Elfving (H-NYL 19120-<br />
holotype!).<br />
Thallus inapparent, endoxylic; hyphal walls <strong>of</strong>ten olivaceous, K+ violet. Phycobiont probably<br />
micareoid, cells c. 5-7 ixm diam.<br />
Apo<strong>the</strong>cia numerous, immarginate, convex-hemispherical or tuberculate, black, matt, 0-1-<br />
0-3 mm diam, or up to 0-4 mm diam when tuberculate. Hymenium 23-30 /xm tall; upper part<br />
(epi<strong>the</strong>cium) fuscous-brown, HNO3— , K- but pigment dissolving and fading into solution;<br />
remaining (lower) part dilute yellowish brown; hymenium sometimes tinged violet in K (evident<br />
after brown pigment has dissolved). Asci clavate, 19-28x7-9 /am. Spores oblong-ellipsoid,<br />
ovoid-oblong or bacilliform, simple or rarely a few 1-septate, 6-9xl-5-2-3 /am. Paraphyses<br />
numerous, hyaline throughout, c. 1 /xm wide in mid-hymenium but <strong>of</strong>ten widening above to T5<br />
/am; sparingly branched and sometimes anastomosing, but becoming richly branched above<br />
where <strong>the</strong>ir entangled apices, toge<strong>the</strong>r with <strong>the</strong> brown pigment, form a ± well delimited<br />
epi<strong>the</strong>cium. Hypo<strong>the</strong>cium c. 70-160 /am tall, pale, dilute yellowish brown, K— , HNO3—<br />
Excipulum reflexed, dilute to dark fuscous-brown, K— but partly dissolving into solution;<br />
hyphae radiating, branched and anastomosing, c. 0-7-OT /am wide, sometimes widening to 1-5<br />
/am towards <strong>the</strong> outer edge.<br />
Pycnidia <strong>of</strong> two types: (a) partly immersed to ± sessile, black, matt, 40-80 /am diam; wall<br />
olivaceous, K-l- violet; conidia (mesoconidia) oblong-ellipsoid, oblong-ovate or obovate, c.<br />
3-5-4-7X1-4—T8 /am; (b) immersed between surface wood fibres, black, c. 4 /am diam; wall<br />
olivaceous, K-l- violet; conidia (microconidia) narrowly cylindrical, 4-4-5 xO-7-0-9 /am.<br />
Chemistry: Sections <strong>of</strong> apo<strong>the</strong>cia C— ; material insufficient for analysis by t.l.c.<br />
Observations: M. rhabdogena resembles M. elachista in apo<strong>the</strong>cial pigmentation and anatomy,<br />
but differs in its endoxylic thallus, smaller and mostly simple spores, and smaller, matt<br />
black pycnidia. M. rhabdogena is similar in appearance and spore characteristics to M. misella.<br />
.