q 



MYXOMYCETES. 3 



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

 Didt/miutn micfocephahun, Chev. Byss. f. 11 (1837). 

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

 Didymium Wallrotlui ', Rabh. Fl. Crypt., 2289 (1844). 

 Didymium porphyropus, DR. & M., Fl. Alg., 409 (1846). 



32. Didymium physarioides. (Po-s.) 



Sporangia not numerous, cylindrical, flattened, crowded together 

 upon a common strongly-developed substratum, as it were combined 

 altogether into one ; sporangia irregularly hemispherical, difforrned, 

 either without a stem, or with a very short stem attached to the 

 substratum ; columella large, common to all the sporangia, form- 

 ing a chamber divided into pseudo-cells, filled with irregular gang- 

 lions composed of small granules of lime ; capillitmni of stout 

 threads, usually simple, only rarely branched, furnished with 

 numerous fusiform dull-violet swellings ; spores dull-violet, with a 

 thick membrane, very spinulose, -012--014 mm. Rtfki. Mon. s 153. 



On stumps, moss, &c. (Figs. 147, 175.) 



Spumaria physarioides. Pers. Sym., 163 (1809). 

 Didymium pli ysarioides, Fr. Gas\, 21 (1817) ; Eng. Fl., v., 314 ; 

 Cooke Hdbk., No. 1132. 



33. Didymium sinapinum. Cooke. 



Sporangia clavate or cylindrical, attenuated at the base, standing 

 on a membranaceous hypothallus, sometimes singly, more usually 

 in small clusters, nearly black below, farinaceous and sulphury- 

 yellow above, as if sprinkled with mustard powder; columella not 

 evident ; capillitiurn very scanty, of thin threads, which are somr-- 

 times entirely absent; external scales of the sporangium contain- 

 ing yellow granules of lime ; spores violet, -0075 mm. diarn., nearly 

 smooth. 



On dead leaves. (Fig. 245.) 



A very curious, distinct, and apparently undescribed species, 

 which we have only met with once, at Forden. 



Sub-Genus 3. Acioniscium. 



"Walls of sporangia single or double ; columella snow-white or 

 brownish-white, as also the stem when present. 



34. Didymium squamulosum. A. % S. 



Sporangia either hemispherical and flattened, or exactly globose, 

 always with the stem slightly umbilicate at the base ; stem snow- 

 white, entering within the sporangium, and expanding into a glo- 



D 



