Knowlks — The Maritime and Marine Lichens of Hoivth. 119 



and of a more halopliilous cbaracter. Scurvy-grass, Sea Spurry, Sea Lavender, 

 Thrift, Plantains, and Sea Campion are abundant. Bare patches of ground, 

 sometimes of considerable area, occur here and there by the paths, and 

 amongst the flowering plants. The soil seems to be derived chiefly from the 

 disintegration of very friable and finely laminated shales, masses of which 

 crop out above the surface in many places. It is a stiff, almost white clay, 

 very powdery in dry weather, and very sticky and close in wet weather. 

 These apparent bare patches are covered with a kind of broken skin formed 

 of crustaceous lichens, grey, green, yellow, black, and brown, all mingled 

 togetlier in some places, but in others forming large colonies of pure 

 growths. Dotted here and there amongst tliem is the small moss Phascuin 

 muticum, occupying the little hollows in the surface, and in some places 

 being almost completely buried in the soil. 



On this white clayey soil Acarospora benedarensis, a new species, is one 

 of the most abundant lichens, and is always found in the driest and sunniest 

 situations. The thai] us consists of scattered squamules of all sizes, which 

 sometimes seem to coalesce and form a fissured but more or less continuous 

 growth. It is a very efficient earth-binder. The under-surf'ace of the thallus 

 has apparently no defining layer, and the hyphal filaments penetrate the fine 

 powdery soil, ramifying and branching in all directions, and enclosing 

 particles of soil in their tissues. Lecanora epixindha is frequently associated 

 with it, but is of less vigorous growth, and is seldom fertile when growing 

 on tlie bare soil. Lecanora umbrina is also frequently associated, and forms 

 good colonies. At various places the soil is full of little chips of shale of 

 all sizes and shapes and in all stages of disintegration. These chips and the 

 intervening spaces are thickly covered with the neat little apothecia of 

 various Buellias, of which B. myrlocarpa, B. snxatilis, and B. Schaereri are 

 the most frequent species. Most of the chips of rock are lying loose on the 

 ground, and might easily be stirred by the wind, but the fact that their 

 upper surfaces are covered with these licliens bears strong testimony 

 as to the sheltered nature of the habitat. 



On the outskirts of most of the bare areas a sort of transition vegetation 

 made up of mosses and lichens grows between the crustaceous vegetation 

 and the flowering plants. These three zones may be distinctly seen in Plate 

 VII, fig. 2. The most usual mosses are Pottia Heimii, Weissia rupestris, and 

 Bryum argenteum var. lanatum, and mixed with them are the fruticose and 

 foliose lichens Cladonia sobolifera, C. pyxidata, and Physcia speciosa, also 

 several crustaceous species that seem to prefer these situations to all others, 

 the most abundant being Lecanora leucospeirea, which is fertile only in rather 

 shady spots, Lecanora holophaea, and Bacidia muscorum. Others are also met 



SCIENT. PBOC. R.D.S., VOL XIV., NO. VI. S 



