Lichen communities in the British Isles: A preliminary conspectus

334 P
E.
Caloplacetum marinae DR.
W. James, D. L. Hawksworth and tr-. I?ose
Marine and Maritiftie Cornrrtunities
saensk. acixtstciol. stillsh. rlantll.2, s0 (192s) las "Caktplaca marina-Lss.,'f.
'r'he caloplacetum marinae is the characteristic association of the sub-
10. I.ichen Communities t'.n the British Isles 38s
Frc. 11. Caloplacetunt rnarinae on maritime siliceous rocks. Predominant species:
Caloplaca marina, C. thallincola and Verrucari,a mttura (Mid-Ebudes: Island of
Mull, Ross of Mull, Carsaig Bay.1972, P. W. James).
C. oerruculifera. Lecanora actophila and L. helicopis are faithful to the
association in the British Isles, the former tending to prefer more sunny,
well lit situations. Verrucaria maura is often present (e.g. Fig. 11),
espccially on more sheltered shores where it is often overgrown by
Caloplaca thallincola. In northern and some western areas Arthonia
phaeobaea and Lecania aipospila also form part of this association and may
become locally abundant. Catillaria chalybeia and Lecania erysibe are
often common although these species, unlike the othcrs mentioned above,
are by no means restricted to coastal rocks. Lichina confinis, occurring in
the lowest part of the mesic-supralittoral zone, forms a link with the
Verrucarietum maurae; similarly Xanthoria parietina, characteristic of the
submesic-supralittoral, interconnects with the Ramalinetum scopularis
association.
A more nutrient-cnriched facies of this association, commonly including
Aspicilia leprosescens, Caloplaca "^erruculifera, Lecanora poliophaea,
Rinodina subexigua and the alga Prasiola quadrata occurs on birds' perching
rocks along the shore or near nesting sites. The rare Caloplaca scopularis,
Candelariella arctica and Lecanora straminea may also occur in this
community. The relationship between this facies ancl the Candelarielletun
corallizae is noted on p. 378,