112 THE MYXOMYCETES 



As stated under D. nigripes, this species and D. xanthopus are 

 called varieties only of nigripes. They are so retained in Mycetozoa, 

 3rd edition. Since, however, they are the usual presentation of the 

 species in the United States, it seems wise to let them stand for the 

 present, as here. They are quite distinguishable; D. eximium especially 

 well marked. 



Apparently rare, it yet ranges from New York to Iowa, in rather 

 large colonies. Also Europe, Ceylon, Java. 



12. Didymium squamulosum {Alb. & Schw) Fr. 



Symb. Gast. 19. 1818. 

 PI. VIII, Figs. 159, 160, 161, 162, 163. 



1805. Diderma squamulosum Alb. & Schw., Consp. Fung. 88. 



1815. Licea stipitata DC, Fl. Fr. ed. 2. 101. 



1815. Didymium efiusum Link, Mag. Ges. Nat. Fr. Berl. 7 : 42. 



1817. Trichia pedicellata Poiret, Lam. Encycl. 13 : 373. 



1827. Cionium squamulosum (Alb. & Schw.) Spreng., Syst. Veg. 4 : 529. 



1829. Didymium costatum Fr., Syst. Myc. 118. 



1829. Didymium herbarum Fr., Syst. Myc. 120. 



1830. Physarum liceoides Duby, in DeCandolle, Bot. Gall. ed. 2. 2 : 461. 

 1869. Didymium radiatum Berk. & Curt., Jour. Linn. Soc. 10 : 348. 

 1873. Didymium neglectum Berk. & Br., Jour. Linn. Soc. 14 : 83. 



1873. Didymium fuckelianum Rost., in Fuckel, Symb. Myc, Nachtr., 73. 



1875. Didymium macrospermum Rost., Mon. 161. 



1875. Didymium discoideum Rost., Mon. 162. 



1876. Chondrioderma cookei Rost., Mon. App. 17. 



1876. Physarum tussilaginis Berk. & Br., Ann. Mag. Nat. Hist. 4 ser. 17 : 139. 



1879. Didymium angulatum Peck, Rept. N. Y. State Mus. 31 : 41. 



1888. Didymium cookei (Rost.) Raunk., Bot. Tidssk. 17 : 86. 



1888. Didymium affine Raunk., Bot. Tidssk. 17 : 88. 



1891. Didymium bonianum Pat., Jour, de Bot. 5 : 316. 



1892. Didymium tussilaginis (Berk. & Br.) Massee, Mon. 244. 



Sporangia in typical forms gregarious, globose or depressed-globose, 

 usually stipitate, 0.5-1 mm. in diameter, but ranging through com- 

 pletely sessile and more or less fused sporangia to plasmodiocarps ; 

 peridium a thin iridescent membrane covered more or less richly with 

 minute crystals of lime; the stipe, when present, snow-white or rarely 

 yellowish to orange, fluted or channelled, stout, even; columella white, 

 conspicuous; hypothallus usually small or obsolete; capillitium of 

 delicate branching threads, usually colorless or pallid, sometimes 

 with conspicuous calyciform thickenings; spores violaceous, minutely 

 warted or spinulose, often with clusters of coarser and darker spines, 

 8-1 1 (x. Plasmodium yellow. 



This, one of the most beautiful species in the whole series, is re- 



