284 EXPLANATION OF PLATES. 
Fig. 15. Roccella Moniagnei, Bél.; Angola, Africa. Portion of thallus magnified, showing a, the 
: ordinary punctiform immersed spermogones; }, large lecidine superficial spermogones ; 
and c, cavities left by the falling out of the old lecidine spermogones, 
Fig. 16. Portion of the same thallus more highly magnified, showing the same punctiform or sub- 
papillaform spermogones a, and lecidine ones 6. 
Fig. 17. Sterigmata and spermatia of same lichen. Some of the sterigmata a become degenerate 
and elongated with age. The cavity of the spermogone is occupied by a network of 
delicate ramose filaments b, resembling those of Ramalina. 
Fig. 18. R. intricata, Mont., from Coquimbo. Sterigmata and spermatia. 
Fig. 19. R. mollusca, Ach. (olim Dufourea), from Cape of Good Hope. Portion of thallus magni- 
fied, showing an apothecium a, and punctiform or papilleform spermogones b. 
Fig. 20. Sterigmata and spermatia of same species. 
Fig. 21. Dufourea madreporiformis, Ach., from Switzerland, Portion of thallus magnified, show- 
ing the punctiform spermogones 6. 
Fig. 22. Sterigmata and spermatia of same species. 
Fig. 23. Dactylina arctica, Hook., collected during Franklin’s first voyage to the Polar regions. 
Sterigmata and spermatia. 
Fig. 24. Acroscyphus spherophoroides, Lév., from Sikkim, Himalayas Portion of end of one of 
the thalline ramuscles, showing the spermogone (and its ostiole) a, resembling that of 
Spherophoron coralloides, Pers. 
Fig. 25. Section of one of the spermogones of same plant. The letters have the same references as 
in fig. 30. 
Fig, 26. Sterigmata and spermatia of same plant. 
Fig. 27. Stereocaulon ramulosum, Sw., from Tasmania. Portion of the ultimate segments of the 
thallus, showing the roundish or wart-like spermogones a, 
Fig. 28. Some of the same spermogones, more highly magnified to show the stellate-fissured, indigo- 
blue-coloured ostiole a. 
Fig. 29. Section through one of the same spermogones: a, ostiole; 6, body of the spermogone, 
Fig. 30. Section, much more highly magnified, through one of the same spermogones : a, ostiole ; 
b, cavity, divided into numerous sinuous compartments; d, gonidia; e, medullary tissue 
of thallus ; 7, cortical layer of thallus. 
Fig. 31. Sterigmata and spermatia of same lichen. 
Fig. 32. Two fragments of the same lichen, showing the spermogones b, forming a sort of collar 
round the apothecia a. 
Fig. 33. S. denudatum, Flk., from Antrim, Ireland. End of a thalline ramuscle magnified, show- 
ing the crowded wart-shaped spermogones a. 
Fig. 34. Spermatia of the same plant, partly straight, partly curved. 
Fig. 35. S. alpinum, Laur.; Ben Nevis. End of a thalline ramuscle, showing the crowded wart- 
like spermogones a. 
Fig. 36. S. paschale, Fr., from near Bonhard, Perth. End of a thalline ramuscle, magnified to 
show the terminal wart-like spermogones a. 
Fig. 37. Some of the same spermogones more highly magnified, showing the stellate-fissured 
ostiole a. 
Figs. 38 and 39. Sterigmata and spermatia from specimens of S, paschale, from Bonhard. 
Fig. 40. S. Argus, Tayl., from Campbell’s Island. Portion of end of one of the thalline ramuscles, 
showing an apothecium a, and a collar of wart-like spermogones 6. 
Fig. 41. Portion of ends of thalline ramuscles of same plant magnified, showing terminal spermo- 
gones a, the segments bearing no apothecium. 
Fig. 42. Sterigmata and spermatia of same plant. 
Fig. 43. Spherophoron compressum, Ach., var. australe, Laur., from New Zealand. Portion of under- 
surface of thallus magnified, showing the round ring-like ostioles of the spermogones a. 

