Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 1. 
10. 
Dy. 
12. 
13. 
14. 
15. 
16. 
ia 
18. 
19. 
EXPLANATION OF PLATES. 291 
PrateE XI. 
Illustrative of the genus Parmetia, Ach., Nyl. 
. Parmelia tiliacea, Ach.; Tasmania. Portion of thallus, showing a, apothecia; 6b, papille- 
form spermogones ; and ¢, punctiform spermogones. 
. Section of thallus, showing both papilleform and punctiform spermogones with depressed 
ostioles: a, mature; 6, young. 
. P. tihacea; Scherer exs., 358. Sterigmata and spermatia: a, sterigmata, composed of a 
few irregular articulations ; 6, spermatia—atiached, acicular—double the length of those 
at c, which are free; d, network of ramose, delicate filaments, which grow from among 
the sterigmata into the cavity of the spermogone; e¢, basal tissue from which the sterig- 
mata spring. 
P. perforata, Ach.; Rio Janeiro. Portion of thallus, showing a, apothecia, perforate in 
the centre, and with a ciliated border; 6, punctiform, black, immersed spermogones. 
P. perforata ; North America. Sterigmata and spermatia: a, sterigmata, composed of a 
few delicate articulations ; b, spermatia—free—acicular ; c, network of ramose fila- 
ments, which occupy the cavity of the spermogone; d, basal tissue, which forms the 
outer wall of the spermogone. 
. P. perforata, Ach., var. denticulata mihi; Nepal. Portion of edge of thallus, showing the 
large barrel-shaped marginal spermogones: a, ostiole ; 6, body of the spermogone. 
. One of the same spermogones more highly magnified: a, ostiole; 6, body of spermogone ; 
c, margin of thallus. 
. P. perlata, Ach., var, ciliata, DC. ; Crinan Canal, Argyleshire. Portion of thallus, show- 
ing papilleform spermogones at a, and punctiform ones at 0. 
. Section of thallus, showing both these forms of spermogones: a, papilleform ; 6, puncti- 
form, with sub-depressed ostiole. 
Sterigmata and spermatia from same specimen: a, sterigmata, composed of several irregular 
articulations or cellules; 6, free acicular spermatia; c, network of anastomosing fila- 
ments, which occupy cavity of spermogone ; d, basal tissue, which forms outer wall of 
spermogone. 
P, perlata ; Scherer exs., 360. Portion of thallus, showing spermogones a, which are 
brownish, semi-pellucid, resembling sago grains. 
P. perlata (= P. leteformis, Fée); Cuba. Sterigmata a, spermatia b, and basal cellular 
tissue ¢. 
P. caperata, Ach.; Tasmania. Portion of thallus, showing papilleform or wart-like sper- 
mogones at a, and punctiform ones at b. 
Sterigmata and spermatia from same specimen. Letters have same references as in fig. 12. 
P. Borreri, Ach.; Penzance, Cornwall. Portion of thallus, showing a, apothecia; and 
b, punctiform, black, immersed spermogones. 
P. acetabulum, Dub.; Scherer exs., 547. Portion of thallus, showing a, apothecia; 6, 
papilleform spermogones ; c, punctiform ones. 
Section of thallus, showing the same spermogones, both papilleform a, and punctiform 2 c. 
P. acetabulum ; Scherer exs., 547. Sterigmata and spermatia: a, sterigmata, composed 
of several irregular cells or articulations ; 6, spermatia attached to apices of individual 
articulations of the sterigmata; c, network of anastomosing filaments, which occupy 
the cavity of the spermogone; d, basal tissue. 
P. acetabulum (= P. corrugata, Ach.); France. Sterigmata and spermatia. Letters have 
same references as in fig. 12. 
Pirate XII: 
Illustrative of the genus Parmetia, Ach., Nyl. 
Parmelia physodes, Ach. ; Knock Hill, Crieff. Portion of thallus bearing apothecia a, and 
punctiform, black, immersed spermogones b. 
