PHY S A RUM 93 



The peridium thin, membranaceous, thickly studded with circular, 

 flattened, yellow granules of lime; stipe long, slender, subulate, 

 opaque, pale brown, striate and black below, pale yellow above; col- 

 umella none; capillitium yellow or white, delicate, forming a loosely 

 but regularly meshed network with numerous small round or round- 

 ed granules at the intersections; spores dark brown, delicately warted, 

 7-8 IX. 



This delicate physarum, very fragile and evanescent, seems to be 

 distinct, by reason of its characteristic rounded lime granules, from 

 any similar, stipitate species. It varies a little according to locality. 

 Ohio specimens are a little larger and have thicker and more calca- 

 reous stipes than is usual in those from Philadelphia. The walls of 

 the sporangia when fully matured generally break into several petal- 

 like segments which finally become reflexed. The description given 

 by Berkeley is entirely insufficient. 



In an earlier edition this species was entered as P. obrusseum fol- 

 low^ing the Polish text. Miss Lister who has the type of Didymium 

 obrusseum at hand considers it as representing a phase of Physarum 

 polycephalum Schw. D. tenerrimum Berk. & Curt, is judged the 

 same. P. tenerum Rex is, in any event, certain, and the combination 

 is adopted. 



Rare: — Pennsylvania, Ohio, Louisiana, Texas, Iowa, Portugal, 

 Japan. 



51. Physarum flavicomum Berk. 



Plate XV., Figs, 3, 3 a. 



1845. Physarum flavicomum Berk., Hook. Jour. Bot., IV., p. 66. 



1873. Physarum cupripes, Berk. & Rav., Gre<v., II., p. 65. 



1875. Physarum berkeleyi Rost., Man., p. 105. 



1894. Physarum berkeleyi Rost, List, Mycetozoa, p. 57. 



1899. Physarum flavicomum Berk., Macbr., N. A. S., p. 53. 



1911. Physarum flavicomum Berk,, List, Mycetozoa, 2nd ed., p, 58, 



Sporangia gregarious, small, spherical, at first fuliginous through- 

 out, stipitate; the peridium thin, destitute of lime, iridescent, break- 

 ing up and deciduous in patches, except at the base; stipe twice the 

 diameter of the peridium, brown, fluted, not hollow, tapering up- 

 ward from a small but distinct, radiant hypothallus; columella none; 



