DIDYMIUM 115 



1808. Trichia farinosa Poiret, in Lam. Encycl. 8 : 53. 



1809. Physarum sinuosum Lk., Mag. Ges. Nat. Fr. Berl. 3 : 27. 

 1809. Physarum capitatum Lk., Mag. Ges. Nat. Fr. Berl. 3 : 27. 



1817. Strongylium minus Fr., Symb. Gast. 9. 



1818. Didymium physaroides Fr., Symb. Gast. 21. 

 1827. Cionium lobatum Spreng., Syst. Veg. 4 : 529. 



1833. Cionium far inaceum (Schrad.) Link, Handb. 3 : 410. 

 1889. Didymium fairmani Sacc, Jour. Myc. 5 : 78. 



Sporangia gregarious, hemispheric, depressed, 0.6-1 mm. in diameter, 

 umbilicate below, stipitate or sessile; peridium firm, dull brown in 

 color, frosted with minute crystals of lime, breaking irregularly; stipe, 

 when present, short, stout, dull black, opaque, fluted, arising from a 

 broad base or hypothallus; columella large, prominent, dark colored, 

 rough above, concave below; capillitium of more or less sinuous, 

 usually dark colored threads, sparingly branched, and often with 

 calyciform thickenings; spore-mass black, spores by transmitted light 

 purple, spinulose or rough, 11-14 p. 



A well-marked and common species, distinguished by its depressed 

 sporangium and dark colored, opaque stipe. The latter is usually 

 very short, almost completely concealed in the concavity of the um- 

 bilicate sporangium. The columella is dark colored, forming the 

 floor of the peridial cavity. 



New England to Washington and Alabama, West Indies, Bolivia, 

 Brazil; Europe, Africa, Java. 



15. Didymium minus Morgan 



Jour. Cin. Soc. Nat. Hist. 16 : 145. 1894. 

 PI. VIII, Figs. 166, 167. 



1892. Didymium farinaceum Schrad. var. minus Lister, Mycetozoa 97. 

 1925. Didymium melanospermum Macbr. var. minus Lister, Mycetozoa ed. 

 3. 115. 



Sporangia gregarious, depressed-globose, umbilicate below, whitish 

 or gray, small, about 0.5 mm. in diameter, stipitate; stipe erect, rather 

 slender, black, faintly striate, usually equalling the diameter of the 

 sporangium in length, sometimes shorter, rarely lacking; columella 

 distinct, dark brown, globose or depressed-globose, attaining about the 

 center of the sporangium, rough; capillitium delicate, almost colorless, 

 radiating, sparsely branched; spores in mass black, by transmitted 

 light violet, minutely warted, 8-11 jx. 



Distinguished from D. melanospermum by the smaller size, the less 

 flattened sporangium, the smoother and usually less limy peridium, the 

 longer stem and the smaller, paler, less strongly warted spores; from 



