= 
d 
Fig. 18. 
PYCNIDES OF CRUSTACEOUS LICHENS. 
PLATE XIII. 
Illustrative of the genera Lecidea, Ach., Opegrapha, Ach., Graphis, Ach., Platy- 
grapha, Nyl., and Melaspilea, Nyl. 
l. Lecidea atro-grisea, Del., Ardrum : sterig- 
mata and spermatia. 
2. Ditto, Rostellan: basidia and stylospores. 
3. Ditto, Cork: sterigmata and spermatia. 
4. Ditto, Hopton: spermatia. 
5. Ditto, Hepp's Exs. No. 76: basidia and 
stylospores. 
. 6. Ditto, Schærer’s Exs. No. 212: ditto. 
. 7. L. candida, Web., 'Trigby : sterigmata and 
spermatia. 
. 8. L. canescens, Ach., Aghada: ditto. 
bs 
Ditto, Schærer’s Exs. No. 576: a, normal 
sterigmata and spermatia; 5, abortive 
or degenerate sterigmata. 
.10. L. spheroides, Dicks. (=L. vernalis, 
Ach.), Kew herb.: sterigmata and 
spermatia. 
. 11. L. quernea, Ach., Leighton’s Exs. No. 61: 
a, portion of thallus, magnified, show- 
ing the spermogones; b, sterigmata 
and spermatia. 
. 12. Ditto, Scherer’s Exs. No. 582: sterig- 
mata and spermatia. 
.18. L. geographica, L., Leighton’s Exs. 
No. 129: sterigmata, spermatia, and 
spermogonal filaments. 
. 14, Lecanora calva, Dicks., var. irrubata, 
Ach., Leighton's Exs. No. 213: asci 
(with sporidia), and stylospores in the 
same hymenium. (Vide also Plate IX. 
fig. 34.) 
. 15. Opegrapha vulgata, Ach., Cork: a, thal- 
lus, showing apothecia and spermo- 
gones; 5, section of thallus, showing 
ditto; c, sterigmata and spermatia. 
. 16. Ditto, Kyles of Bute: a, thallus, show- 
ing apothecia and spermogones; à 
sterigmata and spermatia. 
2 
. 17. Ditto, Belfast: a, thallus, showing apo- 
thecia and spermogones; 4, ditto, mag- 
nified, showing ditto; c, section of 
thallus, showing ditto; d, spermatia. 
Ditto, Carrigaloe: a, thallus, show- 
VOL. XXVIII. 
. 909 
ing apothecia and spermogones; 5, 
spermatia. 
Fig. 19. Opegrapha vulgata, Penmanshiel : sterig- 
Fig. 
. 93. 
M. n 
mata and spermatia. 
. Ditto, Queenstown : spermatia. 
. Ditto, Castlebernard: sterigmata and 
spermatia. 
. Ditto, Rostellan: spermatia. 
. Ditto, Norman Law: sterigmata and 
spermatia. 
. Ditto, Glen Nevis: ditto. 
. Ditto, Leighton's Exs. No. 194: ditto. 
. Ditto, Leighton's Exs. No. 69: ditto. 
. Ditto, Schærer’s Exs. No. 582: ditto. 
. Ditto, var. siderella, Ach., Schærer’s Exs. 
No. 96: ditto. 
. Ditto (type), Glenarm : spermatia. 
. Ditto, Retreat, Berwickshire: a, thallus, 
showing apothecia and spermogones ; 
b, sterigmata and spermatia. 
. Spiloma nigrum, 'T. & B., Malham: sper- 
matia. 
. Opegrapha herpetica, Ach., var. rufescens, 
Pers., Leighton's Exs. No. 221: a, 
section of a spermogone ; 4, sterigmata 
and spermatia. 
Ditto, var. rufescens, Scherer’s Exs. 
No. 95: sterigmata and spermatia. 
. Ditto, var. arthonioidea, Sch., Hepp's 
Exs. 
gone; b, sterigmata and spermatia. 
No. 47 : a, section of a spermo- 
. Ditto, var. subocellata, Ach., Leighton's 
Exs. No. 222: sterigmata and sper- 
matia. 
. O. atra, Pers., Yorkshire: a, thallus, 
showing  apothecia and  pycnides; 
b, sections of thallus, showing ditto; 
c, stylospores. 
Ditto, var. hapalea, Ach., Ireland : sper- 
matia. 
. Ditto, var. parallela, Leight.: a, Corra- 
mulzie; 5, Leighton's Exs. No. 245. 
Sterigmata and spermatia. 
2 U 
