232 A Monograph of the Myxogastres. 



and combined laterally to form a flaccid, irregular net ; spores 

 globose, smooth, pale dingy lilac, 10 11 JJL diameter. 

 (Type in Herb., Kew.) 



On moss. W. Africa (Niger Expedition, Barter). 



A very beautiful and distinct species, known at once by the 

 snow-white sporangium, stem, and columella, and the smooth 

 spores. Plant 3 mm. high; stem 2'5 mm. high, sporangium 

 '5 mm. high, a little more in diameter. 



B. Sporangium sessile. 



(In D. spumarioides and D. physarioides, a very short stem is 

 sometimes present.) 



Didymium Alexandrowiczii, De Bary and Rost. 



Sporangia sessile, deformed, not truncate, several often collected 

 in little clusters, rugulose, granulose; columella absent; threads 

 brownish, colourless at both ends, simple or bifurcating and 

 laterally connected ; spores smooth, obscure violet, 10 12 /u, 

 diameter. 



Didymium Chondrodcrma, De Bary and Rost., in Alex. Stroz., 

 p. 89. 



Chondrioderma Alexandrowiczii, Rost., Mon., p. 169, f. 176 ; 

 Sacc., Syll., 1253; Cooke, Myx. Brit., f. 176. 



On wood Britain (Kew) ; Poland. 



Didymium spumarioides, Fr. I x 



Sporangia substipitate or sessile, scattered or densely crowded 

 on a well-developed, white or pale flesh-coloured hypothallus con- 

 taining much lime ; wall of sporangium white or grey, crust of 

 lime pulverulent; columella variable, smooth or irregularly 

 rugulose, white or pale flesh-colour, sometimes almost obsolete ; 

 threads of capillitium about equal, 1*5 2 p. thick, repeatedly 

 bifurcating and connected laterally to form a net, colourless or 

 dingy lilac, spores globose, minutely ivarted, 9 12 /x diameter. 



Didymium spumarioides, Fr., Symb. Gast., 20. 



Chondrioderma spumanoides, Rost., Mon., p. 173, f. 142 145, 



