292 A Monograph of the Myxogastres. 



Physarum didermoides, Rost., Mon.,p. 97, figs. 74, 87; Cooke, 

 Brit. Myx., p. 11, figs. 74, 87; Sacc., Syll., n. 1171; Raunk., 

 Myx. Dan., p. 72. 



Didymium congcstum, B. and Br., Ann. Nat. Hist. (1850), 

 p. 365 ; Cooke, Hdbk., n. 1130. 



Spumaria licheniformis, Sz. (specimen from Schweinitz in 

 Herb. Berk.). 



Exsicc. Sacc., Myc. Ven., 269 (as jfiidymium congcstum, 

 B. and Br.). 



On grass, twigs, bark, &c. Britain (King's Cliffe, Bulmer, 

 Yorks. ; Carlisle); France; Germany; Italy; Russia; Sweden; 

 United States; Ceylon. 



Usually crowded or gregarious in considerable numbers, 

 springing from a tough, common hypothallus ; sporangia 1*5 2 

 mm. long, stem variable in length, usually shorter than spor- 

 angium, generally very weak, flattened or twisted. When 



sessile the sporangia are sometimes shorter than usual. 



4 



(Rostafinski's Synonyms.) 



Spumaria didermoides, Ach.; in Pers., Syn., p. xxix (1801). ' 

 Diderma ollongum, Schum., Saell., n. 1423 (1803); Flor. 



Dan., t. 1973, f. 1 ; Fr., S. M., iii., 103. 

 Claustria didermoides, Fr., S. V. S., 451 (1849). 

 Didymium, congestum, B. and Br., Ann. Nat. Hist. (1850), 



p. 365 ; Cooke, Hdbk., n. 1130. 

 Didymium farinacewm, Purt., M. F., p. 273. 



Physarum imitans, Racib. 



Sporangia hemispherical, umbilicate, greyish-white, dehiscing 

 irregularly, stipitate, erect or slightly nodding, stem subulate, 

 brownish-black, slightly longer than the sporangium, rigid; 

 columella absent, capillitium white, copious, forming an irregular 

 net, nodes irregular, sometimes filled with lime ; spores 9'5 10 

 mm. diam., violet, warted. 



Racib., Myx. Crac., p. 5, f, 3, a, 6; Sacc., Syll., 1205. 



On branches. Poland. Sporangia (stem included) up to 

 1 mm. high. 



