228 A Monograph of the Myxogastres. 



Didymium lobatum, /3. stipitatum, Somm., Fl. Lapp., 210 



(1825). 

 Didymium nigripes, Fr., S. M., iii., 119 (1829) ; Eng. Fl., v., 



313; Cooke, Hdbk., No. 1124. 

 Didymium xanthopus, Fr., S. M., iii., 120 (1829); Berk., Ann. 



N. H., iii. ; Cooke, Hdbk., No. 1126. 

 Didymium iridis, Fr., S. M., iii., 120 (1829). 

 Didymium microcephalum, Chev., Byss., f. 11 (1837). 

 Didymium melanopus, Wallr., Fl. Germ., 2184 (1837). 

 Didymium Wallrothii, Rabh., Fl. Or., 2289 (1844). 

 Didymium porphyropus, D. R. and M., Fl. Alg., 409 (1846). 

 Didymium megalosporum, B. and C., Grev., No. 318. 



Didymium macrospermum, Rost. I, .tq\awM\Oiv> 



Sporangia spherical or hemispherical, very much flattened 

 vertically, umbilicate below, grey, stipitate, membrane of spor- 

 angium colourless or pale brownish; stem generally longer 

 than peridium, dilated at the base into a distinct discoid 

 hypothallus, attenuated above, strongly plicate longitudinally, 

 srwi'Mvhite or yellmoish-white ; columella versiform, discoid, &c., 

 threads of capillitium simple, rarely branching, at acute angles, 

 colourless or pale brown ; spores subviolaceous, strongly aculeate, 

 12 13 jx diameter. 



Didymium macrospermum, Rost., Mon., p. 166; Schroeter, 

 p. 122; Sacc., Syll, n. 1304. 



On trunks. Germany. 



Gregarious; stem three or more times longer than the 

 sporangium, thinner above, much wrinkled, ridges membran- 

 aceous, pellucid, peridium thin, sometimes dehiscing by be- 

 coming ruptured at the base, and almost, all disappearing; at 

 other times torn into shreds which persist. Appears to be 

 allied to Didymium squamulosum, var. costatum, and distin- 

 guished by the flattened sporangium, long stem, and larger' 

 spores. 



(Rostafinski's Synonyms.) 

 (?) Trichia alata, Trent., 1. c., p. 228 (1797). 



