312 CYCLOCARPINEE | LECANORA 
plane, purplish-black, the thalline margin thick, inflexed, crenate, 
persistent ; paraphyses conglutinate, intricately branched, brown 
at the apices; spores 2 in the ascus, ellipsoid, angular from 
pressure, colourless, becoming dark-coloured, 22-44 yw long, 
15-20 p» thick.—Cromb. in Grevillea xviii. p. 70 & Monogr. i. 
p- 463, L. leprothelia Nyl. in Flora lvii. p. 16 (1874) (a sterile 
form); Cromb. in Journ. Bot. xx. p. 274 (1882). 
In the absence of fertile specimens it has not been possible to do 
more than transcribe Th. Fries’s account of this plant. It is evidently 
rare, both here and on the continent. 
Hab. On decayed mosses on the ground in alpine places.—B. M. 
Ben Lawers, Perthshire (the only British record). 
63. L. parella Ach. Lich. Univ. p. 370 (1810) (excl. vars.).— 
Thallus wide-spreading, generally determinate, thickish or thin, 
smooth and submembranaceous or deeply cracked-areolate, whitish 
or greenish-grey, the hypothallus white (K —,CaCl—). Apothecia 
small or moderate in size, the disc concave then plane or becoming 
slightly convex, sometimes granular or wrinkled, pale flesh-red or 
whitish, generally covered with a white pruina(K(CaCl) +reddish), 
the thalline margin thick, prominent, entire or wrinkled-crenulate ; 
paraphyses subdiscrete, slender, unequal, flexuose, simple or 
branched, the tips budding off small cells (the pruina); spores | 
4—8 (rarely 2) in the ascus, ellipsoid or somewhat globose, 45-88 p 
long, 25-50 p» thick ; hymenial gelatine blue with iodine.—Hook. 
Fl. Scot. ii. p. 48 & in Sm. Engl. Fl. v. p. 191; Tayl. in Mackay 
Fl. Hib. ii. p. 137; Cromb. Lich. Brit. p. 54 (incl. var. tumidula, 
excl. vars. Turneri and upsaliensis) & Monogr. i. p. 461 (incl. 
ff. crenularia and porinoides); Leight. Lich. Fl. p. 188 pro parte ; 
ed. 3, p. 201 pro parte. L. pallescens vars. parella and tumidula 
Mudd Man. p. 155 (1861). Lichenoides leprosum tinctorium, 
scutellis lapidium cancri figura Dill. Hist. Muse. p. 130, t. 18, 
fig. 10 (1741). Lichen parellus L. Mant. p. 132 (1767); Lighté. 
Fl. Scot. ii. p. 814; Huds. Fl. Angl. ed. 2, p. 530; With. Arr. 
ed. 3, iv. p. 17; Engl. Bot. t. 727 (as L. perellus). L. tumidulus 
Pers. in Ust. Ann, Bot. xi. p. 18 (1794). Rinodina parella 8. F. 
Gray Nat. Arr. i. p. 453 (1821). Pertusaria incarnata Leight. 
in Trans. Linn. Soe. ser. 2, i. p. 241, t. 33, figs. 1-3 (1877) & 
Lich. Fl. ed. 3, p. 235 (cf. Nyl. in Flora Ixvi. p. 534). 
Easicc. Bohl. p. 60; Cromb. n. 166; Dicks. Hort Sice. 
fasc. x. n. 23; Johns. nos. 140, 141, 142, 144; Larb. Cesar. 
n. 75 & Lich. Hb. n. 300; Leight. n. 8; Mudd n. 125. 
One of the dye-lichens known in early days as the Pérelle or Orseille 
d'Auvergne. The variant spelling perellus instead of parellus reap- 
pears in several of the authors cited. It is a very common lichen on 
stone walls, etc., and grows well in a northern aspect. The apothecia 
are generally abundant and are very variable in size; the thalline 
margin is often very thick (var. twmidula) and prominent, though 
sometimes almost level with the thallus; occasionally the dise is 
