Knowles— T'/je Maritime and Marine Lichens of Howth. 89 



stain are the young slioots, the apothecia, and the pustulated areas. These 

 are tlie most absorbent parts of the lichen. The older and firmer parts do 

 not respond so readily, and sometimes do not change colour at all, or only 

 after repeated applications of the potash, or after it has lain on the 

 surface for five or ten minutes, or even longer. Altogether, I have 

 found the reaction test so unsatisfactory that for tlie purpose of describing 

 the lower Eamalina zone I have followed Weddell, and have grouped all these 

 llamalinas together under li. scopuloriiiii. 



The Lower Ramalina Zone (R. scopulorum). — Ramalina scojnilorum is always 

 found within reach of the spray, and covers with a tufty growth the tops and 

 sea-faces of the large rocks that lie on the shore a little above higli spring-tide 

 level. Where the sea washes the base of the cliffs at high- water, as at Drumleck 

 Point and other places, Bamalina scopulorum rises up the cliffs and forms a 

 broad or narrow zone according to the slope, ^ rising higher in more exposed 

 places. In the lower part of the zone it occurs in irregular tufts here and tliere 

 on the rocks, sometimes associated with Lichina confinis, Placodium lohulatum, 

 and Verrucaria maura. Upwards it overlaps and gradually disappears amongst 

 the upper Eamalinas. Plate IV, fig. 1, shows Ramalina scopulorum as it 

 grows on the rocky flat at Old Boat-house. Here it covers an extensive area, 

 sheltering an undergrowth of Phj'scias and erustaceous species, in places 

 growing side by side with Spergularia rupestris, Aster IVipo/ium, Statice 

 occidentalis, and other halophytes. 



Where Ramalina scopulorum is much exposed to the wind, or where it grows 

 on rooks that receive an unusual amount of splashing from the waves, the fronds 

 are broader, bluntishatthe ends, andhave the surface much rou.ghened by lumpy 

 excrescences, whicli have been described by Orombie (4) and Leighton (12) 

 as spermogones, but which Zopf (31) considers are due to galls. This form 

 answers to the descriptions of R. scojnilorum Ach. var. incrassata Nyl., and is 

 more frequent in rather exposed situations, and on the rocks nearest to the sea. 

 It is seldom fertile, but apothecia are occasionally met with on some of the 

 fronds. 



On dry rocks anotlier form occurs in which the whole plant is smaller, the 

 fronds more slender and uubranched, and the apothecia frequently terminal. 

 This form grows on the shore at Lion's Head, at Worn Hole, and at several 

 other places round the coast. It has the appearance of being a starved form, 

 growing where there is less wind and moisture. 



Other plants were noticed answering to various forms described by 

 Olivier and Harmand, but most of these occurred only as single tufts 

 here and there amongst the typical forms, and seemed to be accidental. 

 The fronds of R. scopulorum sometimes sliowed a tendency to branch, which 



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