EXPLANATION OP PLATES. 87 



Plate XV. 



Fig. 1. Gyaleda geoica? Ach. Cheddar from Mr. Borrer. 

 (p. 33.) 



A. Vertical section of thallus and patellula. b. Sporidia. 



2. Segestrella thelostoma, Fries, (p. 34.) 



A. Vertical section of thallus and peritliecium. a. Ascigerous 

 disk. h. Tunic, c. Dark brown layer, d. d. Pale portion. 

 e. e. Darker ring. ,f-f. Paler ring. g. g- Margin of thal- 

 lodal wart. b. Sporidia. C. Peritheciura as seen from above 

 the letters refer to the same parts as in a. 



3. Verrucaria nitida, Schrad. (p. 35.) 



A. Vertical section of thallus and apothecium. a. Carbonaceous 

 perithecium. b. Pale inner tunic, c. Nucleus, b. Sporidia. 



4. Verrucaria nitida, /3. dermatodes. (p. 36.) 



A. A. A. A. Vertical sections of thallus and apothecium. b. Spo- 

 ridia. 



Plate XVI. 



Fig. 1. Verrucaria rhgponta, Ach. (p. 37.) 



A. Vertical section of thallus and apothecium. b. Sporidia. 



2. Verrucaria hiformis, E. Bot. Suppl. (p. 37.) 



A. Vertical section of thallus and apothecium. b. Sporidia. 



3. Verrucaria hyssacea, Tayl. (p. 38.) 



A. Vertical section of thallus and apothecium. b. Sporidia. 



4. Verrucaria hyssacea {vera)y ScHiER. (p. 38.) 



A. A. Vertical sections of thallus and apothecium. b. Sporidia. 



5. Verrucaria hyssacea, var, stictica, Schleicher, 



(p. 38.) 



A. Vertical section of apothecia. n. Sporidia. 



