232 



Monograph of the Mijocotjastres. 



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

 globose, smooth, pale dingy lilac, 10 — 11 }x 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 B. sjntmarioidcs and D. 2>hi/sarioides, a very short stem is 

 sometimes present.) 



Didymium Alexandrowiczii, De Bary and Rost. 



Sporangia sessile, defm^med, not truncate, several often collected 

 in little clusters, rugidose, granulose ; columella ahsent ; threads 

 brownish, colourless at both ends, simple or bifurcating and 

 laterally connected; sjjorcs smooth, obscure violet, 10 — 12 jut 

 diameter. 



Didymiu'ia Chomlroderma, De Bary and Rost., in Alex. Stroz,, 

 p. 89. 



Chondrioderma Alexcmdrmviezii, Rost., Mon., p. 1G9, f 17G ; 

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



On wood. Britain (Kew) ; Poland. 



Didymium spumarioides, Fr. 



Sporangia substipitate or sessile, scattered or densely crowded 

 on a well-developed, white or imle fiesh-coloured hypothallus con- 

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

 lime ^ndvcrulent ; columella variable, smooth or irregularly 

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

 threads of capillitium about equal, 1"5 — 2 ju, thick, repeatedly 

 bifurcating and connected laterally to form a net, colourless or 

 dingy lilac, spores globose, minutely warted, 9 — 12 ju diameter. 



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



Chondrioderma sjmmarioidcs, Rost., Mon., p. 173, f. 142 — 145, 



