30 COLLEMACEL. [MAGMOPSIS. 
dark violet-blackish ; spores 1-septate, colourless; hymenial gela- 
tine not tinged with iodine. 
From Pyrenidium, with which it is comparable, this differs in having 
the thallus pyrenopsoid and indeterminate; while from Verrucarina, to 
which it has some resemblance, it differs in the apothecia not presenting 
a true pyrenium. The genus as yet includes only two species, of which 
one has been detected in Britain. 
1. M. argilospila Nyl. ex Cromb. Grevillea, xv. (1886) p. 10. 
—Thallus scattered, subfurfuraceous, very thin, olive-black. Apo- 
thecia innate, minute, peridium sufficiently thin, violet-black ; 
spores 0,022-26 mm. long, 0,007-9 mm. thick ; paraphyses slender, 
sparingly present.—Verruearia argilospila Nyl. Flora, 1874, p. 15. 
Verrucaria arenicola Leight. Grevillea, v. (1877) p. 155; Lich. Fl. 
ed. 3, p. 470. 
The plant spreads extensively over the substratum in small, scattered, 
more or less distinct macule. In structure the thallus is densely and 
minutely cellular, each cell containing a minute subglobose gonimium., 
The apothecia in the specimens seen are numerous, and are more con- 
spicuous where ‘the thallus is semi-obliterated. 
Hab. On sandy and clayey soil in upland tracts.—Distr. Local and 
scarce, in W. England; though it no doubt occurs elsewhere.—B. M. : 
Shelton Rough, near Shrewsbury, Shropshire. 
Family 11. COLLEMACEI Nyl. Mém. Soc. Cherb. ii. (1854) 
p. 8; Syn. i. p. 88 (cfr. Cromb. Grevillea, v. p. 76). 
Thallus foliaceous, or fruticulose, or crustaceous, turgid and 
gelatinous when moist, black, brown, dark olive, leaden, rarely 
glaucescent ; gonimia somewhat small, nakedly conjoined, monili- 
form ; medulla not distinct, but confused with the gonimic layer. 
Apothecia most frequently lecanorine, occasionally biatorine, rarely 
endocarpoid, hypothecium colourless ; spores 8ne, rarely numerous, 
very rarely 4ne, ellipsoid, ovoid or fusiform, simple or septate, or 
variously divided, colourless, very rarely brown. Spermogones 
usually with jointed sterigmata, occasionally with simple sterigmata, 
aud short oblong spermatia. 
This family, as now limited by Nylander, comprehends plants which in 
most essential respects are more closely related to each other than those 
referred to it in his previous classification. “It consists of a higher type of 
lichens than the Lphebacei, being superior in structure, and for the 
most part in figure, with the gonimic granules not or scarcely ever simple, 
but more or less (that is, two or several) moniliform’ (hormogonimia, 
Nyl). The thallus also, when moistened, is more turgid, and though 
still somewhat Algoid in external appearance, is almost always much 
better developed.” In regard to the anatomical structure of the thallus 
Nylander, in his observations on “ gonidia &e.” (Flora, 1877, p. 359), has 
pointed out that (in the higher genera at least) the whole thallus is to be 
regarded as one syngonimium. This syngonimium, he adds, zn litt., ori- 
ginates either from a single primitive gonimium, or from the coalescence of 
several gonimia into one syngonimic body. 
