Pl. ceil. aph. 3. HOMOTHALAMEX. _ 395 
A. Thallus gelatinous, when dry cartilaginous ; Colle- 
matideze. 
Thallus crustlike, slightly figured or 
PEEINEUE GN Py ho glo ae we n'a SAILS, PLAcYNTHIUM. 80. 
Thallus pleated tile-wise, roundish ; : 
loles minute, thick, turgid... «. 2. 2.546% ENcuHyLium. 81. 
Thallus rather leaflike, irregular ; 
tubes thick, naked, turgid... 2.0.1... 6s ScyTENIUM. 82. 
Thallus \eaflike ; 
lobes rounded, downy beneath ........ Mattotium. 88. 
Thallus \eaflike; lobes naked, 
rather membranaceous, blackish green LaTHaGRIUM. 84. 
Thallus leaflike; lobes naked, 
membranaceous, greyish ..........++ . Leprocium. 85. 
- Thallus very finely torn an 
S AUTCUICURAS Banana elas in SAMOS PoLycHIpDIuM. 86. 
B. Fhallus with a fibrous axis, bark crustlike. Usneadez. 
Apothecia shieldlike, terminal, edgeless.... Usnea. 87. 
C. Thallus cartilaginous, inside tow-like. Ramalinidee. 
Apothecia shieldlike, terminal, nearly 
BAB MINISSHA HEY CorRNICULARIA. 88. 
Apothecia saucerlike, edged, slightly 
pedicelled; thallus nearly solid ......... RaMaLIna. 89. 
Apothecia saucerlike, edged, not 
pedicelled ; ¢hallus rather pipey...... .. ALECTORIA. 90. 
A. CortematTipER. Thallus entirely gelatinous, homo- 
geneous; when dry hard, cartilaginous, crustlike, leaflike, 
or branched ; apothecia shieldlike, sessile or slightly pedi- 
celled, sometimes when dry coloured in the centre. ‘These 
ought to be moistened before they are examined, as many 
of them have their apothecia of a different colour when 
dry. 
I. 80. PLACYNTHIUM. Acharius. Placynthe. 
Thallus crustlike, slightly irregular or uniform. 
Placynthium nigrum. ~ Black placynthe. 
Thallus crustiike, nearly orbicular, brown-black; mar- 
ginal lobes deeply crenate; central lobes seedlike, slightly 
branched ; apothecia at length convex, black, edged. 
