Fig. 123. Ramalina siliquosa A. L. Sm. Lower zone of fertile plants (after M. C. Knowles, R. Welch, Photo.).
Fig. 124. Sward of young Ramalinae (after M. C. Knowles, R. Welch, Photo.).
Parmelia prolixa is the most abundant of the Parmelias: it covers large spaces of the rocks and frequently competes for room with the Ramalinas, or in other areas with Physcia aquila and Lecanora parella.
A number of crustaceous species which form the sub-vegetation of the Ramalina belt, and also on the same level, clothe the steeper rock faces where shelter and moisture are insufficient to support the foliose forms. “In general the sub-vegetation of the eastern and northern coasts is largely composed of species that are common in Alpine and upland regions. This is due to the steepness of the rocks and also to the colder and drier conditions prevailing on these coasts.” An association of Rhizocarpon geographicum, Lecanora (sordida) glaucoma and Pertusaria concreta f. Westringii forms an almost continuous covering in some places, descending nearly to sea-level.
Fig. 125. Crustaceous communities in the Ramalina belt. Lecanora atra Ach. (grey patches) and Buellia ryssolea A. L. Sm. (dark patches). (After M. C. Knowles, R. Welch, Photo.)
On sunnier and moister rocks with a south and south-west aspect the association is of more lowland forms such as Buellia colludens, B. stellulata, Lecanora smaragdula and L. simplex f. strepsodina.
(2) The Orange belt. “Below the Ramalinas, and between them and the sea, several deep yellow or orange-coloured lichens form a belt of varying width all round the coast. In summer, the colour of these lichens is so brilliant that the belt is easily recognized from a considerable distance.” The most abundant species occur mainly in the following order descending towards the sea: