182 [RoccELLA. 
LICHENACEI. 
34, ROCCELLA DC. Fi. Fr. ii. (1805) p. 334.—Thallus sub- 
fruticulose, usually opaque and .smoothish, somewhat tough, atten- 
uate at the apices, con- 
colorous on both sides, 
medullary layer dense. 
Apothecia lateral, leci- 
devine or irregular,naked 
or pruinose; hypo- 
thecium thick, black ; 
spores oblong or fusi- 
form, straight or curved; 
hymenial gelatine wine- 
red or wine - yellow, 
or sometimes slightly 
bluish with iodine. 
Spermogones lateral, 
with acicular, curved 
spermatia. 
The thallus is more or 
less fruticulose from a 
common base,and insome 
species is of considerable 
size, Itis whitish, rarely 
brownish, in colour, and 
Fig. 37. 
Roccella phycopsis Ach.—a. Section of external 
firm, though sometimes 
from tenuity becoming 
flaccid. The cortical and 
gonidial systems, as ob- 
served by Nylander, Syn. 
i. p. 256 (efr. Flora, 1866, 
p. 198), form a confluent 
portion of the thallus, showing the cortical and 
gonidial layers and a small exterior portion of 
the medulla, x 2U0. 6. Gonidia, x 3850. ¢. Ver- 
tical section of an apothecium, x30, d. Theca 
and paraphysis, x850. ¢. Spores, x500. ff. 
Vertical section of a spermogone, x 30.  g. 
Sterigmata and spermatia, x 500, 
layer, the cortex, which 
is destitute of an epithallus, consisting of medullary filaments thickened 
towards the surface and there densely parallel, external to which are seen 
granular elements, while internally and immediately beneath the cortex 
are the gonidia. The apothecia are lecideine or variously deformed, often 
as in Derina, sometimes as in Chiodecton, with the paraphyses slender or 
nearly moderate, and not unfrequently bifurcate. 
1. R. phycopsis Ach. Lich. Univ. (1810) p. 440. —Thallus 
rounded or slightly compressed, very much branched and densely 
crespitose, whitish or glaucous-brown, more or less sorediiferous ; 
branches subsimple or dichotomously divided (Ca Cl+reddish, sore- 
dia —, medulla [+bluish). Apothecia small, lecideine, black, naked 
or slightly pruinose, somewhat prominent or appressed ; spores fusi- 
formi-oblong, 0,012-16 mm. long, 0,003-4 mm. thick.—Nyl. Syn. 
i. p. 259, t. 8. f. 3; Gray, Nat. Arr. i. p. 426; Cromb. Lich. Brit. 
p. 22; Leight. Lich. Fl. p. 81, ed. 3, p. 74.—Loccella tinetoria 3. 
phycopsis Mudd, Man. p.75. Lichen fucotdes Dicks. Crypt. fase. ii. 
p. 22. Lichen Roceclla With. Arr. ed. 3, iv. p. 42. Roccella tine- 
toria Sin. Eng. Fl. v. p. 221; Mudd, Man. p. 75; Leight. Lich. Fl. 
