282 



observant poets has truly said, appear 



The living stains which nature's hand alone, , 

 Pro'use of life, pours luUh upon the stone, 

 For ever growlDg, where the common eye 

 Cau but the bare and rocky bed descry. 



The lichens nest to the fucoids must have been the earliest vegetatioa upon 

 land, and when they had commenced nothing would destroy them, and the 

 lichens muse be our oldest aerial plants. Some of the rocks of this very North 

 hill are coated with a sooty perennial covering that bears the name of 

 PannelM slyyut, aad it clings so close to the rock as to be with d IE cult y 

 removable from the stone, and thus gives it a sable hue that extends slowly 

 but surely for centuries, yet e/en this cryptogamic vegetation is migratoiy, 

 and no one can teU from where it may have progressed. It may have existed 

 on these rocks for ten thousand years and yet be not original here, but 

 derived from some other point. The air is filled with minute sporules of 

 cryptogamic vegetation, and thus it is that a roof or wall in the course of a 

 few years becomes coveted by a minute though conspicuous vegetation, that 

 owes its origin to the sporules that have been dispersed by the winds or brought 

 down in rain. A rock though of modern age when exposed to atmospheiic 

 action (for the air is full of spores of Alyie, Fungi, and Lichens), soon becomes 

 covered with an escutcheon of pretence, though from what origin or source 

 derived it would be impossible to say. Walls and battlements in like manner 

 nourish ferns, and where after a time there is mould enough derived from the 

 decomposed rock, or from the ashes of dead cryptogams, flowering plants and 

 even shrubs and trees at last appear, till a ruin like Tintern Abbey or the 

 Coliseum at Rome becomes as thickly clothed with vegetation as a rock 

 itself of nature's formation. Such features foim pictorial scenes that attract 

 the eye of poetical observation, and this Lord Bjron has remaiked justly 



and truly — 



I stood within the Coliseum's wall 



'Mid the last gloiies of eternal Ilonis : 



The trees that grew among the broken arches 



Wav'd dark in the still midnight, and the stars 



Shone through the rents of ruin. 



Some cypresses upon the time-worn breach 



Appeard to skirl the horizon, yet they stood 



AVilhin a bow sliot. Where the L^sars dwcit, 



Now dweU the tuneless birds of night, 'miUsl groves 



That spring from riiin'd battlements. 



And twiue their roots with the imperial hearths. 



More than 500 plants have been enumerated in the "Flora Colis.-ea," as colonized 

 by nature on the ruins of the Coliseum at Rome. So on these rocks I have 

 noticed lichens to the number of 254, and my friend. Dr. Holl, who has paid 

 much attention to this tribe, has added many to the amount, while a few have 

 been from microscopic examina,tion referred to the FangL Mosses too have 

 luxuriated in the recesses of these rocks, if not to the same numerical 

 amount of species, yet individually to a greater extent, forming a wide verdant 

 inundation ; and some of the Jangermannias, especially J. TamarUci, have 

 spread sufficiently to give a remarkable local colouring to the rocks-giving 



