in the neighbourhood of Oswestry and Ludlow. 95 



plant hia Gyalecta cupularis, makes the Gyalecta Wahlenbergiana of 

 Ach. * Syn.' his var. /S. of this plant. Now, if what I regard as the 

 Gyalecta Wahlenbergiana of Ach. be indeed that plant, I cannot but 

 confess my surprise at its being united with marmorea. The two 

 plants appear to me " toto coelo distinctse." I first discovered the 

 Gyalecta Wahlenbergiana about twenty years ago upon the rocks at 

 Craig-y-Rhu in this parish, but the habitat there is now lost. I did 

 not find it again till the year 1840 upon the WickliflF Rocks at Lud- 

 low, where it still grows, investing decayed mosses. This plant 

 forms a continuous crust of a pale yellowish colour, and of a sub- 

 stance somewhat between leprous and waxy. The apothecia, which 

 are numerous, appear to be of exactly the same substance as the 

 crust, and are of an urceolate form, having the disc either of a pale 

 yellow, or in some instances of a diluted greenish colour. The 

 border, which is inflexed, is granulated. The apothecia are far more 

 fragile and tender than in marmorea. The plant resembles much, 

 upon a very minute scale, the beginning of a honeycomb. Wahlen- 

 berg's description of his plant, " substantia mollis et subgelatinosa," 

 and its habitat, " in locis obscuris supra muscos putridos," agree ac- 

 curately with our plant, which indeed I can have no doubt is the 

 same as his, and I cannot reconcile myself to its being united with 

 marmorea. 



Lecidea lutea. Upon a single tree at Llanforda, now cut down. 



L. polytropa. Mynydd-y-Myfyr. This is the only English ha- 

 bitat I at present know for this plant. 



L. lucida. Upon sandstone walls about Oswestry, in fruit, but 

 seldom found in this state. 



L. desert arum. Dr. Taylor, to whom I sent this plant, seems in- 

 clined to refer it to cceruleo-nigricans. Mr. Borrer regards it as the 

 desertorum of Acharius. I cannot but regard it as distinct both 

 from cceruleo-nigricans and from Lecidea coronata, and also from 

 quadricolor, with which Ach. unites it. It grows upon the lime- 

 stone rocks here with cderuleo-nigricans, but is much scarcer. It 

 diflfers from this in having the crust more continuous, and in the 

 scales of this being far smaller and flatter, and having to the naked 

 eye somewhat of a filmy appearance. The shields also have not the 

 bluish colour of those of cceruleo-nigricans, nor are they smooth like 

 these, but are of a deep black colour, and appear rough under the 

 lens. In quadricolor again the shields are always some shade either 

 of brown, yellow, or red, and the crust not scaly, but granulated. 

 The quadricolor too grows upon the earth in heathy situations ; the 

 desertorum upon limestone. In coronata again the crust is a conge- 

 ries of minute bluish granules which form also the border of the 

 apothecia, which are of a reddish brown colour. Fries makes quadri- 

 color and desertorum the varieties a. and /3. of his Lecidea decolorans. 



L. canescens. In fruit upon an old oak at Whittington : common 

 upon old oaks, but usually barren. 



L. cceruleo-nigricans. Limestone rocks at Pentregaer, Craig-y-Rhu, 

 and on the Moelydd. 



L. scalaris. Pales of the Hay Park near Ludlow : scarce. 



