Bulletin of the British Museum (Natural History)

118 BRIAN JOHN COPPINS
often with a swollen base up to 3 /xm wide; conidia (microconidia) cylindrical, eguttulate,
4-6x0-8-1 fxm. A few collections with pallid apothecia have associated pycnidia, c. 60-100 /xm
diam, with hyaline walls and containing (often biguttulate) mesoconidia 2-8-4-3X 1-1-3 /xm (see
'Observations' below).
Chemistry: All parts K- , C- , KC— , PD- ; no substances detected by t.l.c.
Observations: Micarea bauschiana is closely related to, and often confused with, M. sylvicola
(q.v.), and the two species often grow together. M. bauschiana is notoriously variable in the
colour of its apothecia, but the full range of variation from pallid to blackish can be seen over
small distances (a few centimetres) in a single population (Fig. 5: p. 30) and the variation appears
to be solely phenotypic.
When growing on iron-rich rocks the thallus of M. bauschiana is often oxydated. In a few
specimens (including types of Lecidea rusticella) this oxydation has extended to the apothecia in
which finely granular, ferruginous material has been deposited (especially in the epithecium and
hypothecium); such specimens have been confused with M. lutulata and species of Protoblaste-
nia.
A few collections from Austria and Scotland (considered here as M. cf. bauschiana) have
entirely pallid apothecia which are accompanied by pycnidia containing mesoconidia (see
description above). Such pycnidia have not been detected in specimens of M. bauschiana with
pigmented apothecia, and it is possible that the former collections represent a distinct taxon.
However, one of these collections (Austria, Steiemark, Graz, Schockl N of St Radegund, 1978,
Poeh (GZU) also has typical (for M. bauschiana) microconidia-containing pycnidia, and it may
be that there is some environmental control (e.g. a response to very low light intensities)
involved in the initiation of the mesoconidial anamorph. Further careful field observations and
laboratory studies are required to establish the status of these seemingly anomalous collections.
Forms of M. bauschiana (s. ampl. ) with pallid apothecia should be compared with the much
rarer M. lithinella {q. v. ) which can be distinguished by its micareoid phycobiont. In addition, M.
lithinella seems not to occur in the ombrophobous, aerohygrophilous Micareetum sylvicolae,
and is a rather ombrophilous, substratohygrophilous species of damp, shaded rocks or stones.
However, I must stress that this ecological interpretation of M. lithinella is based on the limited
data available from the herbarium specimens and requires confirmation by field studies.
Material recently distributed as 'M. bauschiana' in Hertel Lecid. exs. no. 54 is not this species.
It has weakly marginate apothecia due to a well developed excipulum, and a large-celled
(9-17 /xm diam) phycobiont, the cells of which are deeply penetrated by distinct haustoria (as in
M. intrusa). It is probably an undescribed species of Micarea and will be treated in a later
pubhcation following more critical studies.
Habitat and distribution: M. bauschiana is a faithful member of the Micareetum sylvicolae and
grows on rocks, stones, roots, and consolidated soil in dry underhangs in woodlands or sheltered
valleys. In the British Isles M. bauschiana is the commonest member of the M. sylvicola group. It
is particularly common in the north and west but also occurs in suitable situations (e.g. dry stones
in sandy banks in woodlands) in the lowlands of south-west England. It seems to be widely
distributed in Europe but I have not seen enough specimens to make an assessment of any
distributional tendencies. It occurs in the Azores and the Canary Islands, but I have not seen any
additional material from outside Europe.
Exsiccata: Arnold Lick. Exs. 120 (BM, M), 1233 (M). Johnson Lick. Herb. AM p.p., 504 (HAMU).
Larbal. Lick. Herb. 68 (BM), 305 p.p. (LD). Rabenh. Lich. Eur. 648 p. max. p. (M). Zwackh Lick.
Exs. 279A-B, 594A-B, 595 (M).
6. Micarea botryoides (Nyl.) Coppins
(Figs 10b, 35, 38A; Map 5)
in D. Hawksw., P. James & Coppins in Lichenologist 12: 107 (1980). - Lecidea apochroeella var.
botryoides Nyl. in Flora, Jena 50: 373 (1867). - Lecidea botryoides (Nyl.) Zahlbr., Ca/. lich. univ. 3: 740