Fig. 
Fig. 
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EXPLANATION OF PLATES. 289 
Section through thallus, showing the immersed spermogones a. 
Umbilicaria erosa, Hoffm. Monophyllous thallus, showing the minute, black, papilleform 
spermogones a. 
. Section through thallus, showing the immersed spermogones a. 
. U. hirsuta, DC.; Hepp. exs., 117. Portion of thallus, showing a, apothecia; 6, papille- 
form spermogones; c, marginal cilia of thallus; d, cavities with irregular edges, left 
by the falling out of the apothecia. 
. Section through thallus, showing a, an apothecium; 6, immersed spermogones, 
. U.papulosa, Ach.; Schooley’s Mountains, North America. Specimen showing a, apothecia; 
b, spermogones,—very minute, black, punctiform, frequently seated on the pustules 
of the thallus. 
. Section through thallus, showing a, an apothecium; b, immersed spermogones. 
. Neprhomium tomentosum, Hoffm.; Scher. exs., 259. Portion of margin of thallus, show- 
ing marginal spermogones: a, papillaform ; 6, wart-like; ¢, young. 
. Section of one of the same spermogones : a, ostiole; b, body of spermogone. 
Portion of margin of thallus of another specimen of the same plant (Scher. exs,, 259), 
showing the spermogones a, seated on the ends of digitate processes: 
. LV. tomentosum, Hoffm.; Sikkim, Himalaya. Large barrel-shaped spermogones 6, perched on 
the apices of digitate processes c, of margin of thallus: a, ostiole, 
. Two of the same spermogones more highly magnified: a, ostiole. 
. Section of one of the same spermogones: a, ostiole; 6, cavity; c, sterigmata; d, gonidia ; 
e, medullary tissue of thallus ; 7, cortical layer of thallus. 
. Sterigmata and spermatia of same plant. 
. Solorina saccata, Ach., bearing on its surface Spheria urceolata, a; Hepp. exs., 475. 
. Cetraria Islandica, Ach. Portion of thallus, showing the marginal cilia a, which bear 
the spermogones. 
. Portion of same thallus magnified, showing the same cilia and the barrel-shaped spermo- 
gones a at their tips. 
. The same spermogones still more highly magnified: a, ostiole, 
. Portion of thallus of another specimen of the same plant, showing abortive marginal cilia a. 
. Sterigmata and spermatia from different specimens of C. Islandica. 
. C. aculeata, Fr.; spermogones highly magnified: a, ostiole. 
. Platysma nivale, L.; Leight. exs., 43. Portion of thallus, showing the black, wart-like, 
marginal spermogones a. 
. Portion of same thallus magnified, to show the same spermogones : a, ostiole. 
. Section of one of the same spermogones. The letters have the same references as in fig. 33. 
. Sterigmata and spermatia from different specimens of P. nivale, L. 
. P. sepincolum, Hoffm.; Cleveland, Yorkshire. Thallus showing brown papillaform sper- 
mogones a. 
. Some of the same spermogones magnified : a, ostiole. 
. Sterigmata and spermatia of same lichen. 
. P. cucullatum, Hoffm.; Scher. exs., 18. Portion of thallus, showing the black, wart-like, 
marginal spermogones a. 
. Sterigmata and spermatia of same plant. . 
. P. juniperinum, L. ; Scher. exs., 20. Thallus showing the black, wart-like, marginal sper- 
mogones a, 
Sterigmata and spermatia of same species. 
. XXII. PART I. AE 
