Rev. W. A. Lcighton un the British Umbilicariaj. 297 



mentioned in the note, Lich. Brit. 235, as received from Mrs. 

 Merry, the under surface of one was very finely and less con- 

 spicuously granulated, whilst that of the other was very coarsely 

 granulated, but not more so than is observable in Devonshire 

 specimens ! of U. pustulata in the same herbarium. The upper 

 surface was smoother and browner, though still with the pale 

 yellow tinge ; the pustules less numerous and rounder, but still 

 variable. The apothccia were sessile, either simple or gyrate 

 from compression and aggregation. The sporidia in both are 

 identical with those of our U. pustulata, of which we cannot but 

 regard them as varieties or states. 



Specimens of U. Pennsijlvanica ! and of U. jmstulata /S. jiapu- 

 lusa ! from North America, from JNIr. Tuckerman, in herb. Borrer, 

 had sporidia identical with our U. pustulata. 



Fee describes the sporidia of U. pustulata as elliptical, 4-celled. 



Plate X. fig. 19. Section of thallus and apothecium, younger state. 

 Fig. 20. Section of ditto, older state. Fig. 21. Sporidium. 



EXPLANATION OF PLATE X. 



Fiff. 1 . Section of thallus and apothecium of Umbilicaria pustulata, Hoffm., 

 from Tulasne. 



Fiff. 2. Umbilicaria polyphylla, Schrad. : sporidia. 



Fig. 3. Umhilicaria anthracina, Ach. & Schser. Exs. 15-4 : a, ascus and 

 paraphyses ; b, sj)oridia. 



Fig. 4. Sporidia of Umbilicaria flocculosa, Hoffm. 



Fig. 5. Sporidia of Umbilicaria cenea, /3. hyperborea, Schajr. Exs. 150. 



Fig. 5a. 1. Section of tliaUus and apotheofaof Umbilicaria cenea, fi. hyper- 

 borea, Schjer. Exs. 151. 2. Sporidia. 



Fig. 6. Sporidia of U. arctica, Ach. Specimen from Mr. Robson. 



Fig. 7. Sporidia of U. erosa, Ilotfm. 



Fig. 8. Section of thallus and apothecium of U. erosa, IIofFm. 



Fig. 9. Sporidia of U. Muhlenberg ii, var. alpina, from Mr. Tuckerman. 



Fig. 10. Sporidia of U. erosa, from Mr. Tuckerman. 



Fig. 11. Sporidia of U.pelUta, DC. 



Fig. 12. Sporidia of U.vellea, Ach., from himself, in herb. Borr. 



Fig. VS. Sporidia of U. depressa, var. hirsuta, Scha:r. Exs. 137- 



Fig. 14. Sporidia of U. grisea, Hoffm. 



Fig. 15. Sporidia of U. deusta, Linn, and Turn. & Borr. 



Fig. 16. Section of thallus and apothecium of U. proboscidea, DC. 



Fig. 17- Ascus of U. proboscidea, DC. 



Fig. 18. Sporidia of U. proboscidea, DC. 



Fig. 19. Section of thallus and apothecium of U. pustulata, Hofiin., iu a 

 young state. 



Fig. 20. Section of same in a mature state. 



Fig. 21. Sporidium of U. pustulata, IIofFm. 



The sporidia are all equally magnified, and therefore m relative j)ro- 

 portion. 



