in the neighbourhood of Oswestry and Ludlow. 99 



where charcoal has been burnt in our woods being often carpeted 

 over for many square feet with a luxuriant growth of Marchantia 

 polymorpha. In both these instances, the carbonized soil has un- 

 questionably exerted an influence upon the development of the plants. 

 Liebig, in his ' Organic Chemistry,' p. 62, remarks upon the effects 

 of charcoal in promoting the vegetation of plants, and attributes the 

 effect to the charcoal supplying the roots of plants with an atmo- 

 sphere of constantly renewed carbonic acid and air. I cannot but 

 think that the two instances I have now adduced tend to show that 

 it was through the fibres underneath the thallus that the carbonic 

 acid reached the plants in question and affected their growth, and 

 therefore that these fibres do in some degree supply the place of 

 roots in conveying nourishment from the soil. 



Nephroma resupinata. Upon rocks in woody situations ; Craigforda, 

 Craig-y-Rhu, &c. 



N, parilis. In one instance in fruit at Craig-y-Rhu. 



Gyrophora polyphylla. Mynydd-y-Myfyr : very scarce with us and 

 in a dwarfish state. 



Umbilicaria pustulata. Nesscliff, growing very finely upon the 

 red sandstone rocks at that place. 



Cetraria sepincola. Upon some old park pales at Oteley Park near 

 the water. 



C. glauca. Craigforda. 



Borrerafurfuracea. Mynydd-y-Myfyr, and pales of the Hay Park, 

 Herefordshire, near Ludlow. 



Ramalina pollinaria. Dorrington : not uncommon upon old barn 

 doors ; grows also upon some elm-trees at the Lodge near Ludlow. 



Alectoria jubuta. Not common with us. 



Cornicularia aculeata. Craigforda. 



Isidium coccodes. Old oaks, Oswestry. 



/. microsticticum. Rocks, Pentregaer. 



/. corallinum. Craigforda, &c. 



Spheerophoron coralloides and compressum. Ditto, and Mynydd-y- 

 Myfyr. 



Stereocaulon denudatum. Clee Hill and Mynydd-y-Myfyr, &c. 



S. nanum. Upon walls at Sweeney. 



Cenomyce ccespititia. Craigforda : scarce. I have received it also 

 from Mr. Leighton, I think from Haughmond Hill. 



C. sparassa. Hay Coppice, Herefordshire. 



C. deformis. Ditto. 



C. bellidifiora. A barren state of this grows at Craigforda. 



Pycnothelia papillaria. Barren : Craigforda. This is very scarce 

 with us. I never met with it in such perfection as upon the com- 

 mon immediately above the house at Llandrindod Wells in Radnor- 

 shire. 



Addendum to the List of Welsh Lichens. 



Parmelia stygia. Llandegley Rocks, Radnorshire, upon the end 

 of the range next to the village, and upon the side facing the east, 

 Sept. 1844. 



