-14.] BOTANICAL SOCIETY OF EDINBURGH 271 



The marine algae of this shore are not present in very 

 reat variety, but some of the commoner species are very 

 abundant between the tide-marks. Generally they are 

 most plentiful on the rocks, and are more sparsely 

 distributed on the loose stones which take the place of 

 shingle on the lower reaches of the beach. 



The highest zone, covered only at high tide, includes 

 Eiiteromorpha and Pelvetia canaliculata, Due., both of 

 which may be observed growing in close contact to 

 terrestrial plants such as Anneria maritima, Willd. 

 Xext in succession comes Ascophyllum nodosum, Le 

 Jol., with Polysiphonia epiphytically attached, passing 

 towards low-water mark into Fucus vesiculosus, Linn., 

 and Fucus serratus, Linn. xA.ll these are present in great 

 abundance. No less common are Gladophora and Giga/r- 

 tina in the rock-pools, accompanied occasionally by Ulva 

 in the higher zones, and by Corallina in the lower ones, 

 Cladophora being specially abundant in the central zone, 

 while Gigartina is found throughout the region immedi- 

 atel} 7 above low-water mark. 



Other algae, such as Halidrys, Ectocarpus, Porphyra, 

 and Ceramium, are to be found at low water, but are 

 considerably less abundant than the majority of those 

 already mentioned. 



Lami aorta digitata, Linn., and L. saccJiarina, Linn., are 

 both found at or near low-water mark. The latter species 

 is specially abundant in the quieter waters up the loch, 

 where at low tide, for considerable distances along the shore, 

 the frilled edges of its long thallus can be seen protruding 

 from the water a few feet from the shore, while its hold- 

 fasts, attached to rocks and stones, remain unexposed. 



At Toward Point the same species occur, and they are 

 distributed in the same zones. Here, however, the beach 

 shelves much more gradually, leaving a greater extent of 

 shore exposed at low water. The sea here is more open, 

 and the rocks and boulders are exposed to a considerable 

 amount of wave action. These on the west side are pro- 

 fusely covered by the commoner algae, among which 

 AscophylliLin is specially conspicuous in its abundance, 

 favoured by a firm substratum and the gradual slope of 

 the beach which facilitates the retention of moisture 



TRANS. BOT. SOC. EDIN. VOL. XXVI. 20 



