Bulletin of the British Museum (Natural History)

166 BRIAN JOHN COPPINS
reflexed and obscured in older, more convex apothecia; hyaline or dilute olivaceous (K+ violet)
at outer edge; hyphae radiating, branched and anastomosing, c. 1-1-5 /jlui wide.
Pycnidia indistinct but usually present, immersed in areolae; walls hyaline throughout, or
olivaceous (K+ violet) around the ostiole; of three types: (a) c. 60-80 /xm diam, ostiole
sometimes widely gaping; Conidia {macroconidia) curved or hamate, 1-3-septate, 12-26 xc. 1
/Lim; (b) c. 50-100 (xm diam, ostiole often gaping and conidia extruded as a white blob; conidia
(mesoconidia) short-cylindrical or obovate-oblong, apices rounded but often distinctly truncate
at proximal end, sometimes biguttulate, (3-)3-5-5(5-7)xl-l-5 /xm; (c) c. 40-50 /xm diam,
ostiole never gaping; conidia (microconidia) narrowly fusiform or bacilliform, (4-7-)5-5-
7-5x0-7-0-8/>tm.
Chemistry: Thallus K-, PD-; sections of thallus and apothecia C+ orange-red (also, parts
with olivaceous pigment, C+ violet); t.l.c: gyrophoric acid. If thallus is heavily parasitized and
scurfy the C+ orange-red reaction may be difficult to obtain and gyrophoric acid may not be
detectable by t.l.c.
Observations: M. nitschkeana is closely related, and similar in most respects, to M. denigrata
{q.v.) with mainly 1-septate spores, and M. globulosella (q.v.) with ± acicular or rod-shaped
0-3 (-6) -septate spores. Like M. denigrata, M. nitschkeana has three pycnidial anamorphs;
usually only one or two of these states are found on any given thallus, but all three states (plus
apothecia) have been noted on a single specimen from Scotland {Coppins 3369). In the field M.
nitschkeana can be confused with species such as M. cinerea, M. lignaria, and M. peliocarpa, but
these species usually have larger apothecia and areolae, and are quite different when examined
microscopically.
Habitat and distribution: M. nitschkeana is widely distributed in the British Isles at low
altitudes (below 300 m), and is most frequently found on twigs or small branches of various
deciduous and coniferous trees, e.g. Acer, Aesculus, Alnus, Betula, Fraxinus, Prunus padus,
Quercus, Salix, Sambucus, Larix, and Picea; or on the old or dead stems of smaller shrubby
plants, especially Calluna and Ulex, but also Erica cinerea, Myrica, Rosa, Sarothamnus,
Viburnum, and Juniperus. It has been found to be abundant on old stems and Utter of Calluna in
some lowland heaths in eastern England (Coppins & Shimwell, 1971), Scotland and Denmark,
where it is commonly associated with Lecanora conizaeoides and Scoliciosporum chlorococum;
such communities are referable to the Bacidietum chlorococcae . Other associated species on
twigs and small branches include Lecanora pulicaris, L. symmicta agg., L. icmalea, Mycoblastus
sterilis, Fuscidea lightfootii (western districts), Micarea prasina, Graphis elegans, Stenocybe
pullatula (on Alnus) and small thalli of Hypogymnia physodes, H. tubulosa, Parmelia subaurifera,
P. sulcata, Platismatia glauca, Evernia prunastri, and Ramalina fairinacea. It has
occasionally been met with on lignum of fallen conifers (Larix and Pinus) or fence posts, habitats
more characteristic of M. denigrata. Associated species on lignum include Lecanora confusa, L.
symmicta agg. , Lecidea granulosa agg., L. icmalea, Mycoblastus sterilis, Hypogymnia physodes,
Parmelia saxatilis, and Platismatia glauca. Occurrences on rock are rare, but a few collections
have been made on sandstone or flint stones in heathland, with Lecidea granulosa agg., L.
icmalea, and Micarea melaena as associates. It has also been found together with Scoliciosporum
umbrinum on a plastic carton in a heathland in the Isle of Wight (Brightman & Seaward, 1977).
M. nitschkeana is widely distributed through much of northern Europe. In Scandinavia it has a
southern distribution and I have not seen material of it from north of latitude 62°N. It usually
occurs in lowland situations, but it attains higher altitudes in the Alps (920 m) and the Nizke
Tatry of Czechoslovakia (1250 m). Additional phorophytes from extra-British material include
Hippophae (France: dunes near Calais), Vaccinium uliginosum (Germany: Schleswig-
Holstein), and Pinus mugo subsp. pumilio (heathlands of southern Germany). From outside
Europe I have seen only one specimen: USA, northern California (near San Francisco), where it
occurred on fence ppsts.
Exsiccata: Arnold Lick. Exs. Ill (BM ex K, M), 503 A, B (H-NYL, M); 503 C (BM ex K, H-NYL, M),
503 D (H-NYL, M). Arnold Lick. Mon. 48 (BM ex K, M); 270 (BM ex K). Britz. Lick. Exs. 829 (M).