68 THE NORTH AMERICAN SLIME-MOULDS 



Indian-red in color, 0.5 mm. in diameter; sporangium-wall membra- 

 nous, beset with rounded masses of lilac or reddish lime. Stipe erect, 

 broad-based, tapering upwards, calcareous, furrowed, paler than the 

 sporangium or concolorous, 0.7-0.9 mm. long, about 0.1 mm. thick, 

 columella conical or columnar, capillitium delicate, rigid, persistent; 

 lime-knots small, rounded, composed of large, pale lilac, or reddish, 

 spherical granules. Spores pale-brown, almost smooth, 8-9 fi. 



23. Physarum murinum Lister. 



1894. Physarum murinum Lister, Mycetozoa, p. 41. 



1899. Physarum ravenelii (Berk. & C.) Macbr., N. A. S., p. 48. 



1911. Physarum murinum Lister, Mycetozoa, 2nd ed., p. SO. 



Sporangia scattered, globose or perfectly spherical, ashy-brown, 

 rugulose, stipitate ; stipe elongate, pale brown, erect, generally tapering 

 upward, calcareous, brittle; hypothallus none; columella short, hemi- 

 spherical or bluntly conical ; capillitium dense, much as in P. glob- 

 uliferum, the calcareous nodules, umber, brownish or orange-yellow, 

 small ; spore-mass brown ; spores by transmitted light, bright lilac, 

 almost smooth, 7-9 /x. 



A very distinct species, easily known by its peculiar drab-colored 

 peridium and dull brown stalks. The author of the species allows for 

 the capillitial nodes none other tint but brown. Under direct illu- 

 mination many gatherings, especially where the sporangia are well 

 blown out, show nodules of a bright orange tint. 



Not rare in the eastern United States, to Missouri and Iowa. Re- 

 ported also from western Europe. 



Mr. Lister finds Didymium ravenelii Berk. & C, on which P. 

 ravenelii (Berk. & C.) Macbr. is founded, referable to P. pulcher- 

 ripes Pk. 



24. Physarum pulcherrimum Berk. £ff Rav. 



1873. Physarum pulcherrimum Berk. & Rav., Grev., II., p. 65. 



1875. Physarum pulcherrimum (Berk. & Rav.) Rost., Man., p. 105. 



1879. Physarum atrorubrum Peck, Rep. N. Y. Mus., XXXI., p. 40. 



1899. Physarum pulcherrimum Berk. & Rav., Macbr., A^. A. S., p. 49. 



1911. Physarum pulcherrimum Berk. & Rav., Lister, Mycetozoa, 2nd ed., 

 p. 50. 



