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XVI.—PELTIGERA (Willd., Hoffm.) Fée. 
Fée Ess., suppl., p. 129. Mont. Apergu Morph. p.11. Tuckerm. Syn. N, 
Eng. p.19. Scher. Enum. p.19. Norm. Con. p.13, t.1,£6,a,b. Tul. 
Mém. Lich. pp. 17, 44, G4, t.8. Mass. Mem. p.19,t.1,2. Koerb. Syst. 
p.56. Nyl. Syn. 1, p. 322, t.8, £.38-9; Lich. Scand. p.87. Speerschneid. 
in'Bot. Zeit.1857. Th. Fr. Gen. p. 55; Lich. Spitzberg. p.14. Stizenb. 
Beitr. 1. c. p. 166. Schwend. Untersuch. 1. ¢. 3, p. 174, t. 9, f.9. Pelti- 
gere sect., Hoffm. DC. Scher. Spicil. Fr. 8.0. V. p. 240; L. E. p. 41. 
Peltidea, Ach. L. U. p. 98; Syn. p. 237. Eschw. Syst. p. 22. 
Apothecia peltzformia, thalli lobulis productis raro margini antice 
adnata, margine lacero-crenato. Spore e fusiformi aciculares, quadri- 
pluriloculares, demum incolores. Thallus frondosus, subtus villosus 
venosusque, strato corticali ibidem nullo. Stratum gonimicum e 
gonidiis viridibus, aut seepius ceerulescentibus (collogonidiis) constans. 
The general distinction between the Peltigera-fruit and that of Sticta 
lies in the fact that the former is at once peltiform, and originally innate ; 
whereby what in Sticta appears as the upper half of a closed, superficial 
apothecium is reduced in the other to a depressed veil. The margin is 
developed in both in the same way, and that of the present genus, though 
in most of the forms far less regular, and often even obscure, is expressed 
in P. venosa with all the definiteness of that of Sticta; some curious spe- 
cies of which (S. Boschiana, Mont., S. peltigeretla, Nyl.) simulate, in their 
turn, the habit of the Peltigera. 
The genus offers the same fusiform-acicular spores which we find in 
Sticta; but, in distinction from the latter, in which, as regards the great 
mass of species, the spores are fusiform, and only rarely more elongated, 
Peitigera presents, for the most part, the acicular type, and in only 
two, otherwise receding species, do we find it varying to lanceolate, and 
fusiform. As respects colour, in which Sticta and Nephroma are evi- 
dently (considered as members of the colourless series) aberrant, Peltigera 
deviates far less. Its spores rarely shew indications of colour except 
while still enclosed in the thekes;+ and in fact are generally taken for 
colourless. The genus is perhaps, in this respect also, a key to the 
natural position of Nephroma and Sticta. 
A striking feature of the group before us is its elongated, ascendant, 
sometimes digitately divided fertile lobules; but this gradually disap- 
pears in the forms approaching Sticta, and in P. venosa the apothecia are 
marginal. Mr. Wright detected, on islands of Behring’s Straits, a dwarf, 
arctic condition (f marginalis) of P. aphthosa, in which the apothecia are 
1“ Tes spores des Peltidea canina et P. horizontalis semblent incolores vues 
isolément; mais lorsqwelles sont accumulées trés abondamment sur une lame de 
verre, elles y forment des taches fauves Mune couleur aussi intense que le disque 
des scutelles dont elles sont sorties.”—Tulasne Mém. Lich. p. 72. 
