PHYSARUM 43 



to make out what species Fries describes as P. confluens Pers. 

 Rostafinski says D. effusum (Link) Rost. 



In Bull. Lab. Nat. Hist. Iowa, II., p. 156, this species was 

 described as P. leucopJuzum Fr., with which it is indeed closely 

 related by the wrinkled stipe, varying habit, etc., but it differs 

 in the color of the spores and the shape and surface char- 

 acters of the peridium, as well as in the much more strongly 

 calcareous capillitial nodes. See No. 21. N.A.F., 2693, is P. 

 leucoph&um Fr. ; 2694, a form of the present species. Speci- 

 mens collected by the writer in California, which seem to rep- 

 resent P. glaucum Phillips, are certainly referable here ; also 

 Didymium connatum Peck, of which authentic specimens are in 

 the herbarium of Iowa University. 



This species seems to abound everywhere in the Mississippi 

 valley, and probably, as remarked above, ranges to the Pacific 

 Coast. In the eastern states less common. 



New England, New York, Pennsylvania, Ohio, Illinois, 

 Michigan, Iowa, Nebraska, California, Black Hills, South 

 Dakota. 



20. PHYSARUM NICARAGUENSE Macbride. 



PLATE XV., Figs. 7, 7 a, 7 b. 

 1893. Physarum nicaraguense Macbr., Bull. Lab. N. H. Iowa, II., p. 383. 



Sporangia multilobate or compound contorted, below obconic, 

 gray, ribbed with calcareous thickenings ; stem short, fuscous, 

 longitudinally wrinkled ; hypothallus distinct, black ; columella 

 none, although the lime massed at the centre of each sporan- 

 gium simulates one ; capillitium white, densely calcareous, with 

 heavy angular nodules connected with comparatively short 

 threads ; spores violet, globose, spinulose, about 12/u, in diameter. 



This species resembles the preceding in some particulars, 

 especially in the large amount of lime present in both capil- 

 litium and peridium, in the fluted, sooty stipe, and the rough 

 spores. Mr. Lister regards it as the same. Nevertheless, it 

 differs from P. ucfroidcum in many definite particulars. In the 



