CATALOGUE 
oF 
BRITISH LICHENS. 
Family I. EPHEBACET Nyl. Flora, 1879, p. 223. 
Thallus fruticulose, granulose, rarely subsquamulose, slightly 
turgid and gelatinous when moist, dark in colour, cellular in 
texture (without any medullary filaments), cells minute; gonimia 
somewhat large, gonidioid, tunicated, subglobose, glaucous, variously 
arranged, not moniliform. Apothecia biatorine, lecideine, lecanorine 
or pyrenocarpous ; paraphyses various, sometimes wanting ; spores 
8ne, rarely numerous, usually ellipsoid or suboblong, simple, rarely 
l-septate, colourless. Spermogones immersed in the thallus or 
enclosed in thalline tubercules, sterigmata generally simple or 
simplish, spermatia usually very minute, oblong. 
Nylander, in originally distinguishing this family in Flora 1875, p. 103, 
named it Byssacet Fr.; but as the old genus Byssus in the Michelian 
acceptation referred to Chroolepa, which have gonidic thalli, this has 
been named Ephebacet. * 
The family (the diagnosis of which I owe to Nylander) is well cha- 
racterized by the absence of medullary filaments, and by the nature of 
the gonimia, which are tunicated or involved in a gelatinous cellular 
stratum. On the tunic being ruptured, the gonimia, each of which has 
a very thin parietal membrane (more especially visible when suffused 
with ammonia, Nyl. Pyr. Or. p. 48), become free. Various genera re- 
cently separated from Algez belong to this family ; and no doubt, with 
further knowledge, others will be transferred to it. 
Tribe I. SIROSIPHEI Nyl. ex Stiz. St. Gall. Nat. Ges. 
(1876), p. 192; ofr. Cromb. Grevillea, v. p. 76. 
Thallus minute, byssoid, filamentoso-fruticulose, gonimia (siro- 
gonimia) tunicated, variously connate; medullary filaments none. 
Apothecia minute, biatorine or lecideine; paraphyses thickish or 
slender ; spores Sne, ellipsoid, simple or rarely 1-septate, colour- 
less. Spermogones innate ; sterigmata simple, rarely articulate. 
The various genera composing this tribe (of which Nylander has sup- 
plied the diagnosis) consist of minute algoid plants, whose true re- 
lations have for the most part, until recently, been but little understood. 
In addition to those here described there are others which, ocewrring 
only in a sterile or imperfectly developed condition, do not admit of a 
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