130 THE NORTH AMERICAN SLIME-MOULDS 



delphia, is certainly the same thing. The persistence of a 

 minute part of the peridium at or near the base of the sporan- 

 gium is not unusual, and seems an insufficient basis on which to 

 found a species. 



Pennsylvania, South Carolina, New York, Iowa. 



7. COMATRICHA STEMONITIS (Scop.} Sheldon. 

 PLATE VI., Figs. I, i a, I b, 3 c, $d. 



1772. Mucor stemonitis Scopoli, Fl. Cam., II., p. 493-494. 



1774. Mucor stemonitis Schaeffer, Icones. Tab., CCXCVII. 



1780. Stemonitis typhina Wiggers, Prim. Fl. Hols., p. 116. 



1791. TricJiia typhoides Bulliard, Champ, de la France,^. 119, t. 477, II. 



1796. Stemonitis typhina Persoon, Myc. Obs., I., p. 57, in part. 



1805. Stemonitis typhoides (Bull.) D. C., Fl. Fr., p. 257. 



1829. Stemonitis typhoides (Bull.) Fr., Syst. Myc., III., p. 158. 



1873. Comatricha typlioides (Bull.) Rost., Vers., p. 7. 



1875. Comatricha typhina (Pers.) Rost., Mon.,^. 197. 



1895. Comatricha stemonitis (Scop.) Sheldon, Minn. Bot. Stud., p. 473. 



Sporangia gregarious, scattered, cylindric, erect, sometimes 

 arcuate, obtuse, 2-3 mm. high, at first silvery, then brown, as 

 the peridium vanishes, stipitate ; stipe black, about one-half the 

 total height or less ; hypothallus distinct, more or less continu- 

 ous, reddish brown ; columella tapering upward, black, attaining 

 more or less completely the apex of the sporangium ; capillitium, 

 arising as rather stout branches of the capillitium, soon taking 

 the form of slender, flexuous, brownish threads, which by re- 

 peated anastomosing form at length a close network, almost as 

 in Stemonitis, the free, ultimate branches very delicate and 

 short ; spore-mass dark brown ; spores by transmitted light, 

 pale, almost smooth, except for the presence of a few scattered 

 but very prominent umbo-like warts, of which four or five may 

 be seen at one time, 5-7.5 /*. 



This is our most common North American species. It occurs 

 everywhere on decaying wood, sometimes in remarkable quan- 

 tity, thousands of sporangia at a time. The plasmodium, watery 

 white in color, infests preferably very rotten logs of Qnercus, on 

 which in June the sporangia rise as white or pallid columns. 



