242 



HARDWICKE'S SCIENCE-GOSSIP. 



[Nov. 1, 1S67. 



the tree which it affects to more favourable con- 

 ditions of development. Mr. Moore, of Sydney, 

 tells me he has seen Lichen-growth disappear from 

 a tree simply by transferring the latter to a richer 

 soil or more favourable locality, or by supplying it 

 with proper manure. 



It is inconceivable that there should be such 

 unanimity of opinion among arboriculturists, totally 

 devoid of bias or theory, and expressing only the 

 results "of repeated observations in very different 

 quarters of the world, without the existence of some 

 good ground for their assertions. My impression is 

 that arboriculturists are right to a greater extent 

 than are the lichenologists, and that Lichens must 

 be regarded as, in some measure at least, parasitic, 

 drawing the constituents of their thallus from the 

 objects on which they groio. I pointed out in 1856, 

 in my preliminary work on "British Lichens" 

 (p. 50), that the filamentous Lichens, belonging to 

 such genera as Usnea, Ramalina, Evernia, and 

 Parmelia, which coat, with shaggy flowing masses, 

 oak, firs, and other trees, and whose growth is the 

 main subject of dispute between lichenologists and 

 arboriculturists, contain such bases as Silica and 

 Alumina, Lime, Potash, Soda, Magnesia, Manganese, 

 and Iron, in combination, or not, with Carbonic, 

 Sulphuric, Hydrochloric, Phosphoric, or other acids. 

 The most of these could not have been derived from 

 the atmosphere ; and indeed we are shut up to the 

 conclusion that, as in the case of higher plants, 

 they are derived from the surfaces or substances on 

 which the Lichens containing them grow.* This 

 conclusion is further supported by the recorded 

 facts that chemists have detected iron in greatest 

 amount in species affecting ferruginous soils, and 

 silica in those growing "on quartzose rocks, or their 

 debris. I am not, however, prepared to contribute 

 any new facts towards the settlement of the in- 

 teresting question which forms the heading or title 

 of this communication, or of the other equally inte- 

 resting,.but less practicaljand economically important 

 questions, which naturally suggest themselves for 

 consideration in connexion therewith. My purpose 

 is rather to call attention to the paucity and unsatis- 

 factory character of the facts or opinions that have 

 hitherto been recorded, and to invite the record of 

 facts as contradistinguished from mere opinions, 

 bearing upon the following points more especially : 

 I. What is the precise ground on which the 

 assertion is founded that Lichen-growth is detri- 

 mental to timber and other trees ? 



* In a paper by the late Dr. Dundas Thomson, of Glasgow 

 and London, on" The Inorganic Food of Lichens" (Edinburgh 

 New Philosophical Journal, vol. xxxvii., 1845, p. 18/), he says, 

 "Contrary to the usually received opinion Lichens re- 

 quire inorganic matter as part of their food, which they must 

 derive from the localities upon which they are fixed." He 

 points out that the Lichen thallus contains from 5 to 7 per 

 cent, of ash : and that the same inorganic constituents are 

 found in corticolous as in saxicolous species. 



II. In what way does such growth injuriously 

 affect the timber, bark, fruit, or foliage of such 

 trees ? 



III. How far is Lichen-growth a cause of un- 

 healthy or diseased development in the trees on which 

 it ocQurs ? 



IV. How far is it a result of such development ? 



V. To what extent do Lichens draw their con- 

 stituents (A. organic, B. inorganic) from the atmo- 

 sphere ? 



VI. To what extent from their bases of support, 

 —the bodies on which they grow ? 



A BOUQUET EROM HELVELLYN. 



rpHE top of Helvellyn when fairly reached is 

 -■- chiefly occupied by a sort of mossy plain or 

 table-land, probably once formed of sphagnum, 

 which is now dried up and overrun by smaller and 

 more arid mosses, intermixed with very dwarf 

 specimens of thyme grass and other plants, and 

 here and there stiff close bunches of coralline-like 

 Lycopodium alpinum, and netted with the ropes, 

 often yards in length, of the tough, creeping stems 

 of the Tod's-tails, or Stag-horn (Lycopodium cla- 

 vatum), which might easily catch the feet and trip 

 up the unwary pedestrian. These two Lyco- 

 podiums, and perhaps also" the coarser Lycopodium 

 selago, are as fond of exposed barren situations as 

 are some of their congeners, such as Lycopodium 

 undatum and Lycopodium selaginoides of wet 

 sheltered nooks. 



But while enjoying a repose on this beautiful 

 mossy height, we must not forget that Helvellyn, 

 in common with most if not all the lake mountains, 

 is really encumbered with quantities of loose stones, 

 apparently disintegrations constantly going on from 

 the effects of weather on the slaty cleavage of the 

 fundamental rocks, starting up in places completely 

 denuded, far above the surface of the mountain, and 

 adding so much to the savage grandeur of the 

 scenery, as, for instance, " Striding edge," ending 

 in the fine precipices round the Bed Tarn. These 

 detached pieces of rock, by whatever ancient or 

 modern agency they may have been shivered off 

 from the general mass, roll or slide down the sides 

 of the mountain, helped on by the winter snows 

 and torrents and the summer thunderstorms, their 

 course, however, generally guided by some in- 

 equality or furrow-like depression of surface ; and 

 here gliding down, they collect from the dews and 

 rains imperceptible rills of moisture underneath 

 them, which serve as nurseries for many of our 

 choicest and loveliest sub-alpine plants. I do not 

 mean to restrict my bouquet solely to Helvellyn, 

 because on Fairfield, Loughrigg, Oxenfell, Dunmail 

 Baise, and other adjacent and similar localities, I 

 have found the very same plants, and manymorc 

 than I can venture to load the pages of the Gossip 



