198 BRITISH LICHENS. 



and he will find on the bark a number of species which, carefully 

 removed by the aid of a knife and placed in paper, will afford him hours 

 of interesting study on reaching home. Parmelia saxatilis or Ramalina 

 fraxina may be the first to meet his eye, while, on closer investigation, 

 he will discover Lecnnora subfusca or Lecanora varia, with their abundant 

 apothecia, covering the surface of the bark. Near the base he will 

 probably observe patches of a nearly white crustaceous Lichen, having 

 here and there warty protuberances, with openings in the centre, revealing 

 to a close inspection an almost concealed hymenium — this will be 

 Pertusaria faUax. We cannot pretend to enumerate the various species 

 that will reward a careful examination of such a tree as the one we have 

 supposed, but we would advise the collector to secure a fair specimen of 

 all species he can find, for although he may obtain nothing very rare, he 

 will obtain sufficient with which to begin his study. If he can get into 

 the vicinity of rocks which have been exposed to the weather for a long 

 period, or old stone or brick walls, he will not return empty-handed, for 

 a vast number of species find their home on such surfaces as are pre- 

 sented by these. Wherever the tint of colour differs from the natural 

 oolour of the rock we may reckon on finding a Lichen. The artist pro- 

 duces his picture by the skilful combination of inorganic pigments — not 

 so Nature — she produces the effects we admire by the aid of highly- 

 organised vegetable growths, and we may rest assured, if we see the bark 

 of trees or the surface of rocks presenting shades of brown, green, or 

 yellow, they arise from the presence of the objects of our search. Within 

 the compass of a square yard a dozen species of Lichens may be flourish- 

 ing in all their beauty. If the search happens to be on a rocky sea-coast, 

 the student will probably find some of the Ramalinas above the line of 

 high-water mark, such as R. polymorpha, R. scopulorum, ovR.cuspidata. He 

 will probably find also some of the Roccellas, as R. tinctoria or R. fusi- 

 formis, and if his search be pursued lower down on the rocks, washed by 

 the waves, he may find the curious little Li china pygmcea, which resembles 

 a miniature seaweed, but is a true Lichen ; and the dark olive green 

 Verrucaria maura, which looks, at a little distance, like a coat of paint. 

 Inland rocks, except they be of the very softest nature, will afford 

 innumerable species of interest to the collector. Slate rocks are rich in 

 those splendid species, Parmelia caperata and Physcia parietina, and the 

 striking variety of Parmelia saxatilis, called omphalodes. Limestone rocks 

 abound with the brilliant specimens of Placodium callopismum and 

 P. murorum, with Lecideas, Verrucarias, and other interesting species. Nor 

 will the earth itself fail to yield a goodly array of Cladonias, Cetrarias, and 

 Lecideas. In fact, whenever the pocket lens is brought to bear with judg- 

 ment on rock or tree, or hedge-bank, some species will reward the search. 



Here it may not be out of place to offer a few hints on collecting 

 Lichens. 



Select well-grown and complete specimens. I have seen some men con- 

 tented with a mere fragment of a specimen, destitute of any apothecia, 

 and showing nothing of the margin, where often much of the distinctive 

 character of a species lies. It is as though a single stone from a house 



