Didymium. 233 



151 ; Cooke, Myx., p. 38, f. 142145, 151 ; Schroeter, p. 123 ; 

 Sacc., Syll., n. 1269. 



Chondrioderma stromateum, Rost., Mon. Append., p. 18, f. 151. 



Diderma farinaceum, Peck, 26th Report State Mus., N. Y., 

 p. 74. 



Exsicc. Fckl., F. Rhen., 2495 (as Carcerina spumarioides, 

 Fr.) ; Rab., F. Eur., 432 (as Carcerina spumarioides, Fr.) ; Cke., 

 F. Brit, Ed. II., 825 ; Roum., Fung. Gall, 1682. 



On living or dead leaves, moss, &c. 



Britain (Highgate, Shere, Scarboro') ; France ; Germany ; 

 Sweden ; Belgium ; Italy ; United States ; Australia. 



The present species was placed by Rostafinski in the genus 

 Chondrioderma, from which it differs, according ta our inter- 

 pretation of the genus, in the pulverulent, instead of porcelain- 

 like coat of lime. Very variable in colour and size of the 

 columella, but well marked by the highly-developed hypo- 

 thallus, which sometimes becomes so thick as to suggest the 

 idea of a stroma. Sporangia from *5 1'5 mm. diam., circular 

 or irregularly angular from mutual pressure, sometimes the 

 stroma, when very thick, forms a short stem-like projection; 

 the colour of the stroma and columella varies from chalk-white 

 through pale tints to pale flesh-colour. 



(Rostafmski's Synonyms.) 



Spumaria physarioides, Pers. Syn., 163 (1801). 



Physarum didermoides, Fries, Herb. 



Spumaria alba, Schum. Saell., No. 1414 (1803); Fl. Dan., 



t. 1798, f. 2. 



Didymium spumarioides, Fr., Symb. Gast., 20 (1818). 

 Physarum stromatium, Link, Hdbk., iii., 409 (1833). 

 Carcerina spumarioides, Fr., S. V. S., 451 (1849). 

 Diderma spumarioides, Fr., S. M., iii., p. 104 ; Eng. FL, vol. v., 



p. 311; Cke., Hdbk., No. 1109. 



Didymium physarioides, Rost. '*yn * 



Sporangia cylindric-oblong, often crowded arid deformed, 

 seated on a well-developed hypothallus, sessile or with a short 



