COLLEMA. | COLLEMEL. 53 
Approaches f. marginale, but distinguished by the larger spores, which, 
as observed by Nylander /. ¢., entitle it to rank at least as a subspecies. 
In the only two specimens seen by me the apothecia are numerous, and 
almost crowded in the centre. 
Hab. On caleareous rocks in upland districts Distr. Found only in 
N.W. Ireland.—B. M.: Tullywhee Bridge, co. Galway. 
18. C. cristatum Hoffm. Deutsch. Fl. ii. (1795) p. 101.—Thallus 
intricately laciniate, thickish, olive-’or blackish-green (I+red); 
lacinise short, undulato-crisp, inciso-crenate at the margins. Apo- 
thecia rather large, somewhat plane, reddish-brown, the thalline 
margin at length crenulate; spores fusiformi-oblong, somewhat 
narrower at both apices, 3-septate, irregularly murali-locular, 0,026- 
34 mm. long, 0,010-12 mm. thick.—Schaer. Enum. (1850) p. 225 ; 
Cromb. Journ. Bot. 1874, p. 334; Leight. Lich. Fl. ed. 3, p. 22.— 
To this belongs as an old state Collema subplicatile Cromb. Journ. 
Bot. 1874, p. 147, non Nyl. Flora, 1875, p. 297, which latter belongs 
to the section of C. chalazanum. As already observed, Lichen crista- 
tus Huds., Linn., &. is a variety of Collema tena. 
From the closely allied C. melenum this differs in the imbricato-aggre- 
gate iaciniz with inciso-dentate margins, in the larger apothecia with 
erer.ulate thalline margin, and in the slightly different spores. These 
discinguish it in its typical condition, though whether they make it speci- 
fi ally distinct is doubtful. The apothecia, when fully developed, are of 
considerable size, and only sparingly present. 
Hab. Among mosses on old walls and on rocks in maritime and up~ 
land districts.— Distr. Found only in W. England, the W. Highlands, 
Scotland, and 8.W. Ireland.—B. M.: St. Michasls Tor, Devonshire: 
near Cirencester, Gloucestershire. Island of Lismore, Argyleshire ; 
Killin and Craig Tulloch, Perthshire. Killarney, co. Kerry. 
19. C. polycarpon Koerb. Par. (1865) p. 417.—Thallus small, 
radiato-laciniate, appressed, dark-green or reddish-black (I+ pur- 
plish-red) ; laciniee narrow, short, complicate, suberect in the centre, 
more expanded and depressed at the circumference. Apothecia 
small, numerous, plane, or at length somewhat convex, dark-red or 
blackish, the thalline margin thin, entire; spores oblong or fusi- 
formi-ellipsoid, more constantly 3- rarely 5-septate, locular, 0,418— 
27 mm. long, 0,006-7 mm. thick.—Cromb. Journ. Bot. (1873) 
p- 1382, 1874, p. 334; Leight. Lich. Fl. ed. 3, p. 22.—Collema 
multifidum 6. polycarpon Scher. Spic. (1842) p. 532. Collema 
stygium Scher. Spic. p. 544, Lich. Helv. n. 434; Cromb. Journ. 
Bot. 1874, p. 334; Leight. Lich. Fl. ed. 3, p. 23. Nylander 
observes in ltt. that while C. stygiwm Del., may be the plant of 
Scherer, it is probably not pure, and is besides only a MSS. name, 
while that of Scherer and Arnold is @. polycarpon (conf. Flora, 
1883, p. 105).—Brit. Exs.: Cromb. n. 103; Larb. Lich. Hb. n. 1. 
Might be taken for a smaller state of C. melenum, but the characters 
given separate it. The apothecia are usually abundant over the thallus, : 
and sometimes are so numerous as almost to obliterate the lacinize. 
