114 A Monograph of tlie Myxogastres. 



inside the sporangial wall, and the smooth or obsoletely marked 

 threads of the capillitium. The present genus is allied to 

 Arcyria; in Arcyria parqdoxa we meet with lumps of lime and 

 of organic matter on the inner surface of the sporangial wall, 

 but the capillitium is characteristic of Arcyria. 



The present genus is yet more closely allied to Ophiotheca; 

 in fact it is impossible to say where one ends and the other 

 commences ; in Perichaena the capillitium threads are typically 

 without external markings, whereas in Lachnobolus the threads 

 have distinct raised markings, but in each genus species occur 

 deviating from the typical idea and in the direction of the other 

 genus, and it is doubtful whether the presence or absence of 

 markings on capillitium threads alone, even if constant, is of 

 sufficient value to constitute a generic distinction. 



Distrib. Europe ; Borneo ; W. Australia ; Canada ; United 

 States. Species 9. 



Perichaena depressa, Libert, (figs. 118 120). 



Sporangia usually gregarious or much crowded, polygonal 

 from mutual pressure, very much depressed, and almost plane 

 above, dehiscing in a circumscissile manner, brown, sometimes 

 with a purple tinge, polished ; mass of capillitium and spores 

 bright orange-yellow; capillitium usually well-developed, threads 

 variable in width, smooth, rarely notched or furnished with 

 rudimentary scattered spinules ; spores globose, minutely warted, 

 9 12 \i. diameter. 



Perichaena. depressa, Lib., PI. Or. Ard., Fasc. IV., n. 378 ; 

 Host., Mon., p. 292; Cke., Myx. Brit., p. 77; Sacc., Syll, 

 1434; Raunk., Myx. Dan., p. 54. 



Exsicc Sacc., Myc. Ven. 500; Ellis, N. Amer. Fung., 1218; 

 Roum. Fung. Gall., 2113; Fuckel., Fung. Rhen., 2200; Lib., PI. 

 Crypt. Ard., Fasc. IV., n. 378. 



On wood, &c. Up to 1 mm. diameter. Characterized by the 

 very much flattened sporangia and bright yellow mass of spores. 



Britain (Carlisle) ; Germany ; Bohemia ; Belgium ; Italy ; 

 France ; United States. 



