PERICII^NA.] . ARCYRIACE^. 197 
of this gathering embrace the varieties given as "a. scabra" and 
svinosa'' by Sclii-ceter, and also those of the numerous specimens ot 
Comuvia Wrightu Rost., from the United States, including the type 
from Cuba gathered by Wright. A specimen from Mr. Morgan, from 
Ohio, stands alone in having small spores 7 to 8 /x diam. ; in other 
respects it is typical. 
The circumscissile form of the sporangia is not met with in any of 
the collections, or in my own gatherings. From the original account ot 
Trichia circumscissa by WaUroth, it is possible that the specimen 
described by him was Periclmna depressa ; the specific name given by 
Currey is therefore here adopted. 
Hab. On dead bark.— Lyme Eegis, Dorset (L:B.M.163); Herb. 
Broome (B. M. 308) ; Ceylon (K. 1712) ; Philadelphia (L:B.M.163) ; 
Ohio (L:B.M.163) ; Iowa (L:B.M.163) ; Cuba (B. M. 699). 
2. P. depressa Libert, PI. Crypt. Ard. Fasc, iv., No. 378 
(1837). Plasmodium? Sporangia sessile, crowded, polygonal 
from mutual pressure, depressed, 0-5 to 1 mm. diam., purple- 
or red-brown, dehiscing along the margin with a well-defined 
lid; sporangium- wall of two layers, the outer cartilaginous 
charged with brown granular matter, more or less closely com- 
bined with the membranous, smooth, inner layer. Capillitium 
an abundant web of branched, slender, yellow threads, 1-5 to 
2-5 fji diam., minutely warted and marked with irregular con- 
strictions. Spores golden-yellow, minutely warted, 8 to 12 /a 
diam.— Rost., Mon., p. 292; Cooke, Myx. Brit., p. 77; Mass., 
Mon., p. 114. Perichcena artocreas Berk. & Bav., in Grev., ii., 
p. 68. Perichcena irregularis Berk. & Curt., in Grev., ii., p. 68. 
Ophiotheca irregularis Mass., Mon., p. 132. Stegasma australe 
Oesati in Rabenh., Fungi Eur., No. 1865 (1874). Perichcena 
australis Berl., in Sacc. Syll., vii., p. 422; Mass., Mon., p. 119. 
Perichcena applanata Mass., Mon., p. 116. 
Plate LXXr., B. — <i. sporangia, x 20 capillitium, x 280 ; capillitium 
and spore, x 600 (England). 
The type specimen of P. ajij^lanata Mass., from Brisbane (K. 153), 
is characterised by the outer layer of the sporangium- wall having a 
superficial crust of angular crystals of lime, which gives the sporangia 
a lilac-grey colour ; in all other respects, in the abundant and 
minutely warted capillitium, and in the spores measuring 10 to 
12 /X diam., it agrees with P. depressa. Deposits of lime on the 
sporangium-wall are of frequent occurrence both in the latter species 
and in P. popuUna, and although they are unusually abundant in the 
Brisbane specimen, the character is not of sufficient importance to 
give specific distinction. The type specimen of P. artocreas Berk. 
& Rav. from S. Carohna (K. 1027 and B. M. 697) appears to be 
P. depressa with abundant capillitium, and spores measuring 8 to 10 /x ; 
the sporangia are polygonal, depressed, pale brown ; the inner layer of 
the sporangium-wall is smooth, and not papillose as in P. variabilis. 
The type specimen of P. irregularis Berk. & Curt, from S. Carolina 
(K. 1706) is typical P. depressa. A type specimen of Stegasma australe 
Ces. (B. M. 1034), is in imperfect condition, but it appears to be P. 
depressa from the many broken pieces of minutely warted capillitium, 
and the spores, which measure 10 to 11 /x diam. 
