Arcyria. 147 



Arcyria (Erstedtii, Rost. 



Sporangia ovate, in the typical form, stipitate, stem shorter 

 than sporangium, firm, erect ; like the sporangium, dirty brown ; 

 mass of capillitium and spores brown, often with a red tinge; 

 capillitium forming a rather dense net, threads cylindrical, 

 3 5 fi diameter, with scattered, elliptical, swollen portions, spar- 

 ingly and equally covered with slender spines of various lengths ; 

 spores smooth, 8 10 /x diameter. 



Arcyria (Erstedtii, Rost., Mon., p. 278, fig. 196 ; Sacc., SylL, 

 vii., 1, n. 1468; Raunk., Myx. Dan., p. 60, t. 3, f. 1 ; Cke., 

 Myx. Brit., fig. 196. 



On wood. Britain (Burnham Beeches, Bucks) ; Denmark ; 

 Russia. 



Characterized by the net, without free arms, having its 

 threads swollen at intervals, and sparingly and equally covered 

 with slender spines of variable length, the longest about equal 

 to diameter of thread. 



Arcyria umbrina, Schum. 



Sporangia single or gregarious, on a thin, shining hypothallus, 

 ovate, stipitate. Receptacle on the inner side provided with 

 a network of delicate thickenings. Stem brownish-black, longer 

 than the sporangium. After dehiscence of the sporangium the 

 capillitium enlarges itself but slightly. Capillitium and the 

 mass of spores ochre-brown. Tubes of net of the capillitium 

 with thickenings in the form of half-rings encircling the thread 

 in a spiral, without regard to the thickenings 2'5 3 /x, broad. 

 Spores smooth, 5 7 n diameter. 



Arcyria umbrina, Schum., t. 3, f. 5. Schumacher: Fl. Saell., 

 No. 1479; Fl. Dan. Tab., 1975, fig. 1; Raunk., Myx. Dan., 

 p. 108, t, 3, f. 8. 



On rotten stumps. Summer ; autumn. Near Copenhagen. 



When comparing the two Arcyria species delineated in the 

 Flora Danica, 1975, figs. 1 and 2, with the descriptions of them, 

 it will be seen that the text to fig. 1 in reality belongs 



