160 



657. GYROPHORA VELLEA, Ho/m. 



a. Thallus. 



Note. This is the species figured by Pereira in his Mat. Med., vol. ii., 

 pt. i., p. 20, fig. 19, right-hand figure. It is one of those known under the 

 name of tripe de roche. It is also found in this country on alpine rocks. 



658. LECANORA TARTAREA, L. 



a. Thallus. 



6. Ditto, prepared. 



c. Ditto. (0-round Cudbear.) 



Note. Cudbear is made, like litmus, by the action of air and am- 

 moniacal liquor upon the above species and other lichens. The name 

 cudbear is a corruption of Cuthbert, the Christian name of Dr. C. Gor- 

 don, under, whose management it was first manufactured at Leith, in 

 1777. See Per. Mat. Med., vol. ii., pt. i., p. 37. Lecanora tartarea is a 

 crustaceous lichen. 



659. PARHELIA PERLATA, L. 



a. Thallus. 



Note. This lichen forms No. 2 quality of Socotra orchella weed. It 

 is one of the commonest lichens on trees and rocks in this country. 



660. PELTIGERA CANINA, L. 



a. Thallus. 



Note. This foliaceous lichen is sold by herbalists under the name of 

 ground liverwort, and is used by them for liver complaints. It is very 

 common in hedge-banks in damp, hilly districts ; and is readily recog- 

 nised by its grey colour and broad fronds, which are white and fibrous 

 underneath. It is, however, chiefly imported from Germany. For fig. , 

 see Per. Mat. Med., vol. ii., pt. i., p. 19, fig. 16. 



661. BOCCELLA TINCTORIA, D.C. 



a. Thallus. (Lima thick Orchella Weed.) 



Var. /3 HTPOMECHA, Ach. 



a. Thallus with apothecia, from the Cape de Verde Islands. 



662. ROCCELLA FUCIFORMIS, Ach. 



a. Thallus. (Orchella Weed.) 



I. Ditto, ditto, with apothecia, from Madagascar. 



c. Ditto. (Socotra Orchella Weed, Shennah, no. 1 quality.) 



d. Ditto, from Aden. Presented by Dr. J. Vaughan. 



e. Litmns. 

 /. Orchil. 



Note. Eoccella fuciformis occurs in this country only in the extreme 

 south of England, as in Devon, Cornwall, Isle of Wight, and Jersey ; but 

 not in sufficient quantity for commercial purposes. Boccella tinctoria 

 does not occur in Britain ; B. phycopsis has usually been mistaken for it. 

 Specimens 6, c, and d consist chiefly of E. Montagnei, which differs from 

 B. fuciformis in being flaccid. B. phycopsis is readily distinguished by 

 its cylindrical branches, dense habit, and the yellow colour of its point 

 of attachment to the rock. For fig., see Bentley and Trimen, Med. 

 Plants, tab. 301. Orchil is made by mixing the powdered orchella weed 

 with urine, and exposing it to the air. To make litmus, potash, soda, or 

 lime is added. See Per. Mat. Med., vol. ii., pt. i., p. 33. 



