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Cincinnati Society of Natural History. 



yellow ; the basal portion thicker and more persistent, naked 

 and plicate, red-brown. Stipe red-brown, long, slender, pli- 

 cate, rising from a small hypothallus. Capillitium of thick 

 tnbules, forming a net-work with wide expansions at the 

 angles; the nodules of lime large, numerous, yellow, angu- 

 larly lobed and branched. Spores globose, very minutely 

 warted, pale violaceous, 9-10 mic. in diameter. 



Growing on old stalks of Zea mays. Sporangium with the 

 stipe 1-1.5 mm. in height and .4-6 mm. in diameter, the stipe 

 always longer than the sporangium. I find it in abundance 

 on old stalks of Indian corn, but never on anything else. 



VII. PHYSARUM Pers. Sporangium globose, depressed 

 globose or irregular, stipitate or sessile; the wall a thin mem- 

 brane, with an outer layer of minute roundish granules of 

 lime, irregularly dehiscent. Stipe present or often wanting, 

 never prolonged within the sporangium as a columella. 

 Capillitium of slender tubules, forming an intricate net-work, 

 the extremities attached on all sides to the wall of the spor- 

 angium; the tubules more or less expanded at the angles of 

 the net-work, and containing at varying intervals nodules of 

 lime. Spores globose, violaceous. 



Physarum is the central genus of the Physaracecz from 

 which all the others are detached by characters which for the 

 most part are unimportant. 



§1. Lapidium. Lime in the capillitium scanty; the 

 nodules small, roundish, ellipsoidal or fusiform. 



A. Sporangium stipitate. 



a. Sporajigia regular. 



1. Physarum nutans Pers. Sporangium orbicular, very 

 much depressed, the base concave or umbilicate, stipitate, 

 cernuous; the wall a thin pellucid membrane, thickly covered 

 with minute white or yellow roundish scales of lime, break- 

 ing up into irregular fragments, which often remain attached 

 to the capillitium. Stipe long, slender, tapering upward, 



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