70 CYCLOCARPINEE [LEPTOGIUM 
9. L. humosum Nyl. in Mém. Soc. Sci. Nat. Cherb. p. 90 
(1857) & Syn. Lich. i. p. 119 (1858).—Thallus effuse, consisting 
of closely aggregate lobulate granules mostly small with larger 
granules intermixed, brown or brownish-black. Apothecia small, 
somewhat concave, black ; spores 4 to 8 in the ascus, ovoid, or 
oblong-ovoid, variously septate and muriform, 20-34 w long, 
8-16 » thick.—Cromb. in Journ. Bot. xxii. p. 195 (1885). 
Distinguished by the coarsely granular, very dark thallus. 
Nylander has included with this species Leptogiwm tetrasporum Th, Fr. 
in Vet. Akad. Férh. 1864, p. 276 (see Crombie Monogr. i. p. 65). 
Hab. On mortar of walls.—B. M. Port Gorey, Island of Sark (the 
only British locality). 
Thallus of small lobes ; growing on soil, mortar, ete. 
10. L. pusillum Nyl. in Mém. Soc. Sci. Nat. Cherb. v. p. 90 
(1857) & Syn. Lich. i. p. 121.—-Thallus effuse, papillate-lobate, 
the lobules erect, crowded, olive- or greenish-brown. Apothecia 
small, concave then plane, somewhat prominent, becoming dark- 
reddish, the margin concolorous ; spores ovoid or broadly fusi- 
form, 3—4-septate and muriform, 18-30 » long, 8-10 » thick.— 
Cromb. Lich. Brit. p. 7; Leight. Lich. Fl. p. 30; ed. 3, p. 27. 
Kasicc, Larb. Cesar. n. 54. 
Somewhat similar to L. biatorinum in the appearance of the 
thallus, though more developed and more densely papillate, but 
chiefly distinguished from it by the darker-coloured superficial 
apothecia. 
Hab. On mortar of old walls and on chalky soil.—Distr. Local 
and rare in the Channel Islands and §S., W. and N. England.— 
B, M. St. Brelade’s Bay, Jersey; St. Peter’s Port, Guernsey ; Bon- 
church, I. of Wight; Shiere, Surrey ; Freshford, near Bath, Somerset ; 
Cheltenham, Stroud, Cowcombe, Chedworth Woods and near Ciren- 
cester, Gloucestershire. 
11. L. tenuissimum Koerb. Syst. Lich. Germ. p. 419 (1855).— 
Thallus effuseof deeply cut or crenate thin lacinie congested 
into a dense crust, olive- or brownish-green. Apothecia moderate 
in size, deeply concave, becoming somewhat plane, embedded 
among the laciniz, reddish-brown, the margin pale, thickish ; 
spores ovoid or oblong, generally narrower at the ends, 3—5-septate 
and muriform, 18-34 pw long, 11-13 » thick.—Mudd Man. p. 46; 
Cromb. Lich. Brit. p. 7; Leight. Lich. Fl. p. 35; ed. 3, p. 26. 
Lichen tenuissimus Dicks. Pl. Crypt. fase. i. p. 12, t. 2, fig. 8 
(1785); With. Arr. ed. 3, iv. p. 61; Engl. Bot. t. 1427. Collema 
tenuissimum Ach. Syn. p. 328 (1814); Hook. in Sm. Engl. Bot. v. 
p. 213. Polychidium tenuissimum 8S. F. Gray Nat. Arr. i. p. 401 
(1821). 
Exsicc, Mudd n. 4. 
Distinguished from other soil species by the pulvinate growth of 
the thallus. The apothecia are rather large with age, but they remain 
