324 LICHENACET. [UMBILICARIA. 
plane; spores often obsoletely curved, 0,013-16 mm. long, 0,005-6 
mm. thick.—Cromb. Journ. Bot. 1882, p. 273. 
Differs very much from U. pustulata in the external appearance of the 
thallus, though agreeing with it in the character of the apothecia. It is 
well characterized by the somewhat rigid thallus having the upper sur- 
face minutely areolate and the lower smooth and glabrous, as also by the 
apothecia being constantly lecanoroid and not becoming gyrose. The few 
British specimens are smaller than those of more boreal regions. They 
are, however, well fertile, the apothecia being numerous, though some- 
what small. 
Hab. On granitic boulders in exposed alpine places.—Distr, Found 
only very sparingly on one of the N. Grampians, Scotland—B. M.: 
Summit of Cairntoul, Braemar, Aberdeenshire. 
55. GYROPHORA Ach. Meth. 
(1803) p. 110; Nyl. Flora, 1875, 
p. 303.—Thallus naked or fibrillose 
beneath. Apothecia lecideine, usually 
more or less gyroso-plicate; hypo- 
thecium usually brown; spores 8ne, 
simple, colourless; hymenial gela- 
tine bluish and then sordid wine-red 
with iodine. Spermogones immersed ; 
spermatia short, cylindrical. 
202) 
Distinguished from Umbilicaria by 
the apothecia being lecideine, with the 
perithecium differing in texture from QO 
the cortex. The structure of the thallus CO) 4d 
scarcely differs from that of subgen. 
Agyrophora. The apothecia are 
either simply lecideine or beautifully 
gyroso-complicate, each individual epi- 
thecium being narrow and margined. 
The spermogones have the spermatia ¢ 
similar in size to those of Umbilicaria. 
In several cases the chemical reaction 
of the medulla with CaCl affords a valu- 
able aid in the discrimination of spe- =a id 
cies otherwise with difficulty separable 
from each otuer. Fie. 5 
fig. 54, 
; Gyrophora cylindrica Ach.—a. 
1. G. grisea Turn. & Borr. Lich. Br. Vertical section of thallus, with 
928 _| on lateral portion of a spermo- 
(1839) p. 236.—Thallus monophy] Bork, C000. b, Vertical ees. 
lous, thin, minutely areolato-papillate, tion of an apothecium, x30. 
somewhat lobed and crenate at the c. Theca and paraphysis, 
margins, greyish-white or mouse- x 300. d. Three spores, x 500. 
coloured; beneath finely granuloso- é. Sterigmata and epermatia, 
areolate, scabrous, naked or sparingly au 
fibrillose in the centre, blackish or greyish (K_, CaCl yea) Apo- 
thecia at length convex, immarginate, gyroso-plicate; spores 0,014-18 
