36 COLLEMACEI. [LEPTOGIBIVM. 



rather difficult to an-anpre in the series. From the gonimia, it seems 

 to haye its most appropriate place in this tribe. 



1. L. dendriscum Xvl. Flora 1873, p. 195 (note). — Thallus very 

 much branched, intricate, slender, ronnded or obsoletely compressed, 

 opaque, greenish, or pale-yellowish at the base. Ai)othecia small, 

 pale or pale-red, the epitheciiim at length somewhat convex : spores 

 0,010-16 mm. long, 0,006-S mm. thick. — Cromb. Journ. Bot. 1874, 

 p. 337 ; Leight. Lich. Fl. ed. 3, p. 13. — Lepioriium dendriscum Nyl. 

 Syn, i. (1858) p. 135. Lepiorjium Mooreii Hepp, Carroll, Journ. 

 Bot. 1865, p. 287 ; Cromb. Lich. Brit. p. 10 ; Leight. Lich. Fl. 

 p. 27. Ephebe hyssoides 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 

 resemblanc^ to Leptoyium muscicola, near to which it was originally 

 placed by Nylander; but the gonimia and other characters remove 

 it from Leptoyium 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-bro-wni tubercles, have not been seen rightly developed. 



Hah. On mossy trunks of ti-ees in moist upland situations. — Dktr. Very 

 local and rai-e in S.W. Ireland. — B. M. : Glengariflf and Glena, Killamey, 

 CO. Iverrv. 



Tribe II. COLLEMEI Xyl. Mem. Soc. Sc. Xat. Cherb. ii. 

 (1854) p. 9 : Syn. i. p. 93 {cfr. Cromb. Grevillea, v, p. 76). 



Thallus usually membranaceous, lobed, laciniate or microphylline, 

 occasionally fruticuloso-ramose, rarely crustaceous or granulosa ; 

 gonimia glaucous-green, more or less monilifurm ; cortical layer 

 either cellular or indistinct. Apothecia lecanorine, sometimes 

 biatoriue, rarely endocarpoid ; spores 8nse, 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 spemiatia. 



This extensive tiibe (notwithstanding its recent limitation) consists of 

 genera diverse in various particulars, yet sufficiently connected by mutual 

 links. It contains the best-developed members of the family, and in 

 number of species, if not in their fiequency of occurrence, is very well 

 represented in our Islauds. 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. PI. Horn. (1825) p. 297; Xyl. Syn. 

 i. p. 93. — Thallus pulvinate, thinly crustaceous or fruticuloso- 

 divided : gonimia (spcirogonimia) either solitary or few, usually 

 scattered among the filaments : cortical lavcr obsoletely ccl- 



