PEEICH^NA.] AECYRIACE*. 197 



of this gathering embrace the varieties given as "a. scabm" and "^. 

 spinosa " by Schroeter, and also those of the numerous specimens of 

 Cornuvia Wrightii 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 fi 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 of 

 Trichia circnmscissa by Wallroth, it is possible that the specimen 

 described by him was Perichcena depressa ; the specific name given by 

 Currey is therefore here adopted. 



Hab. On dead bark.— Lyme Regis, 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. Pasc, 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. CapiUitium 

 an abundant web of branched, slender, yellow threads, 1'5 to 

 2-5 /A diam., minutely warted and marked with irregular con- 

 strictions. Spores golden-yellow, minutely warted, 8 to 12 /a 

 diam. — Eost., Mon., p. 292; Cooke, Myx. Brit., p. 77; Mass., 

 Mon., p. 114. Perichcena artocreas Berk. & Rav., in Grev., ii., 

 p. 68. Perichcena irregularis Berk. & Curt., in Grev., ii., p. 68. 

 Ophiotheca irregularis Mass., Mon., p. 132. Stegasma australe 

 Cesati in Eabenh., Fungi Eur., No. 1865 (1874). Perichcena 

 OMstralis Berl., in Sacc. SylL, vii., p. 422; Mass., Mon., p. 119. 

 PerichoBna applanata Mass., Men., p. 116. 



Plate LXXr., B. — a. sporangia, x 20; J. capillitium, x 280; c. capillitium 

 and spore, x 600 (England). 



The type specimen of P. applanata 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 ju, 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 ip the 

 Brisbane specimen, the character is not of sufficient importance to 

 give specific distinction. The type specimen of P. artocreas Berk. 

 & Rav. from S. Carolina (K. 1027 and B. M. 697) appears to be 

 P. depressa with abundant capillitium, and spores measuring 8 to 10 ft ; 

 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 

 Oes. (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 ;u diam. 



