PELTIGERA | PELTIGERACEX cl 
Thallus often wide-spreading, submonophyllous or polyphyllous, 
corticate on the upper surface ; not corticate below, tomentose or 
nerved and more or less rhizinose. Algal cells blue-green, Nostoc, 
bright-green Dactylococcus. Apothecia marginal, adnate on the 
upper surface of the frond ; spores elongate-fusiform, 3- or pluri- 
septate, colourless or brownish. Pycnidia sometimes present, 
with ovoid acrogenous spores. 
In most of the species of this genus the alge are blue-green. In 
a few the gonidial zone is bright-green, but in these there are always 
present groups of Nostoc cells enclosed in cephalodia, as small tubercles 
on the upper or lower surface, or within the thallus. The veins below 
are due to intercalary growth in the upper cortical layers, causing 
stretching and pulling apart of the tomentum below so that the 
white medulla becomes more or less exposed. The genus is divided 
into two sections :— 
Thallus with blue-green gonidia................sceceeeeees i. HUPELTIGERA. 
Thallus with bright-green gonidia and with cepha- 
OLD Dc lny 8 inte SRE ge Al oS Se eee eee an ii. PELYIDEA. 
§ i. EupettTicerRA Hue in Nouv. Arch. Mus. Hist. Nat. Paris 
sér. 4, ii. p. 92 (1900). 
Algal cells blue-green (Nostoc) ; cephalodia not present. 
Thallus downy above. 
1. P. canina Willd. Fl. Berol. p. 347 (1787).—Thallus large, 
spreading, rather thick, of large rounded lobes usually downy 
above, brownish-green when moist, glaucous-grey or fawn- 
coloured when dry, beneath whitish, with prominent pale nerves 
and long white rhizinz of fasciculate hyphe. Apothecia moderate 
in size, roundish, becoming revolute, brown or brownish-red, 
entire or slightly crenulate at the margin; spores elongate- 
fusiform, 3—5-septate, 66-70 p long, about 4 pw thick.—Mudd 
Man. p. 82, t. 1, fig. 22 (excl. vars.) ; Cromb. Lich. Brit. p. 29 
(incl. var. membranacea) ; Leight. Lich. Fl. p. 107; ed. 3, p. 101 
(excl. f. erispa) ; var. membranacea Nyl. Syn. i. p. 324 (1860) ; 
Cromb. Monogr. i. p. 288. Lichenoides peltatum terrestre cinereum 
majus, foliis divisis Dill. in Ray Syn. ed. 3, p. 76, n. 87 (1724). 
Lichenoides digitatum cinereum, Lactuce foliis sinuosis Dill. Hist. 
Muse. p. 200, t. 27, fig. 102 = (1741). Lichen caninus L. Sp. Pl. 
p- 1149 (1753); Huds. Fl. Angl. p. 454; Lightf. Fl. Scot. ii. 
p. 845; With. Arr. ed. 3, iv. p. 69; Engl. Bot. t. 2299. 
Peltidea canina Ach. Lich. Univ. p. 517 (1810); 8. F. Gray Nat. 
Arr. i. p. 428 ; Hook. Fl. Scot. ii. p. 60 (excl. var. rufescens) & in 
Sm. Engl. Fl. v. p. 215; Tayl. in Mackay Fl. Hib. ii. p. 153. 
Exsicc. Croall n. 492; Johns. n, 26; Larb. Cantab. n. 28 ; 
Leight. n. 141; Mudd n. 59. 
Distinguished from other species by the white under surface, and 
the numerous long white rhizine. The thallus is variable in size, 
