36 COLLEMACEI. [LEPTOGIDIUM. 
rather difficult to arrange in the series. From the gonimia, it seems 
to have its most appropriate place in this tribe. 
1. L. dendriscum Nyl. Flora 1873, p. 195 (note).—Thallus very 
much branched, intricate, slender, rounded or obsoletely compressed, 
opaque, greenish, or pale-yellowish at the base. Apothecia small, 
pale or pale-red, the epitheeium at length somewhat convex; spores 
0,010-16 mm. long, 0,006-8 mm. thick.—Cromb. Journ. Bot. 1874, 
p. 337 ; Leight. Lich. Fl. ed. 3, p. 13.—Leptogium dendriscum Nyl. 
Syn. i. (1858) p. 185. Leptogiwn Mooreii Hepp, Carroll, Journ. 
Bot. 1865, p. 287; Cromb. Lich. Brit. p. 10; Leight. Lich. Fl. 
p. 27. Ephebe byssoides Carring. Trans. Bot. Soc. Edinb, vii. p. 411, 
t. 10. f. 2. 
This is one of the exotic lichens which find their way from sub- 
tropical regions to the S.W. of Ireland. It has a somewhat general 
resemblance to Leptoyium muscicola, near to which it was originally 
laced by: Nylander; but the gonimia and other characters remove 
it from Leptogium to an inferior position in the family. The apothecia 
are not visible in any of the Irish specimens, the organs described as 
such being spermogones. These, however, though not unfrequent as 
minute pale-brown tubercles, have not béen seen rightly developed. 
Hab. On mossy trunks of trees in moist upland situations.— Distr. Very 
local and rare in 8. W. Ireland.—B. M.: Glengariff and Glena, Killarney, 
co. Kerry. 
Tribe Il. COLLEMEI Nyl. Mém. Soc. Sc. Nat. Cherb. ii. 
(1854) p. 9; Syn.i. p. 93 (ofr. Cromb. Grevillea, v. p. 76). 
Thallus usually membranaceous, lobed, laciniate or microphylline, 
occasionally fruticuloso-ramose, rarely crustaceous or granulose ; 
gonimia glaucous-green, more or less moniliform; cortical layer 
either cellular or indistinct. Apothecia lecanorine, sometimes 
biatorine, rarely endocarpoid; spores 8nze, rarely numerous, ellip- 
soid, ovoid or rarely fusiform, usually septate and divided, occa- 
sionally simple, colourless. Spermogones with the sterigmata ar- 
ticulate, occasionally simple or subsimple, and oblong, ellipsoid or 
bacillar spermatia. : 
This extensive tribe (notwithstanding its recent limitation) consists of 
genera diverse in various particulars, yet sufficiently connected by mutual 
links. It contains the best-deyeloped members of the family, and in 
number of species, if not in their frequency of occurrence, is very well 
represented in our Islands. The plants for the most part very greedily 
. imbibe moisture, and we often find a marked contrast in the appearance 
of the thallus when moist or dry. 
12. SYNALISSA Fr. Pl. Hom. (1825) p. 297; Nyl. Syn. 
i. p. 93.—Thallus pulvinate, thinly crustaceous or fruticuloso- 
divided ; gonimia (speirogonimia) either solitary or few, usually 
scattered among the filaments; cortical layer obsoletely cel- 
