Rev. W. A. Lcightoii on the British Umbilicarisp. 281 



lockhart Hills, jMaugliaii, Dr. Greville. North of England ! Rev. 

 John Harriman in herb. Jiurrer. By the lake by the ascent of B(^\\ 

 Nevis ! northern ridge of Ben Cruachan ! Mr. Borrer. Caer 

 Caradoe, Shropshire ! states a. b. & c. growing together. 



a. monophjlla. Thallus of a single peltate leaf. 



" Tlinllus consisting generally of a single peltate leaf from 

 1 to 2 inches in diameter, attached to the rock by a central cal- 

 lous disk, orbicular, ilattish, but curled and reflexed at the edges, 

 which are irregularly lacerated or divided into a few unequal 

 shallow lobes : the upper surface dark greenish-brown when 

 moist; when dry, of a rusty-brown approaching to black, mi- 

 nutely dotted and sprinkled with a coarse sooty efflorescence, 

 very copious in some specimens, but in others rare, sometimes a 

 little wrinkled about the centre, and occasionally bearing nume- 

 rous small leafy scales : the vnder surface dark brown or black, 

 naked, quite smooth in general, though now and then most 

 minutely granulated and pitted, more copiously in some speci- 

 mens than in others, with small depressions, which are often so 

 numerous as to give it an absolutely reticulated appearance : 

 substance coriaceous, very thin, so as to be almost membranous ; 

 flexible when moist, but rigid and brittle when dry. Tricce rare, 

 scattered about the thallus, sessile, but attached only by the 

 centre, orbicular, their margin slightly elevated and entire, their 

 disk convex; the (jyri most frequently concentric, sometimes, but 

 rarely, forming irregular groups.^' — Lich. Brit. 



Specimens from Upsal, Sweden ! Fries fil., and from the 

 Pyrenees ! M, Philippe, in my own herbarium, agree with our 

 British plants. 



b. poh/phylla, T. & B. Thalli small, clustered, curled. 

 Whitwick Rocks, Leicestershire ! Rev. A. Bloxam. 



Thallus composed of numerous small remarkably curled leaves 

 arising from a common central disk and growing in an irregu- 

 larly orbicular grouj), the diameter of which is not greater than 

 that of the simple leaf of nionophylla. 



c. squamigera. Thallus rough with small scale-like leaves. 



d. erusa. Thallus with ragged and perforated edges. 



The tricsc are figured in ' E. Bot.' from foreign specimens 

 received from ])r. Swartz. None of the British specimens in 

 Mr. Borrer's herbarium bore any fructification, nor those in 

 Schicrer^s Liehenes Exsiccati. 



Closely allied to ct. polyphijlla, and apparently approximating 

 to e. erosa by the state d. erosa. 



Plate X. fig. 4. Sporidia. 



