PHYSARUM 3 1 



calcareous nodules rounded, inclined to form a pseudo-columella 

 in the centre ; spore-mass black ; spores purplish, distinctly 

 rough, 10-12 fi. 



A very beautiful and distinct species. It is a Pliysarum with 

 the outward form of a Diderma. Not common. Specimens 

 are before us from Ohio, Indiana, Michigan, Iowa. 



5. PHYSARUM CONTEXTUM Persoon. 



PLATE IX., Figs. 3 and 3 a. 



1796. Diderma context um Persoon, Obs. Myc., I., p. 89. 



1801. Physarum contextum Persoon, Syn. Meth., p. 168. 



1829. Diderma contextum Persoon, Fries, Syst. Myc., III., p. in. 



1873. Diderma ochroleucum B. and C., Grev., II.. p. 52. 



Sporangia distinct, sessile, densely crowded, sub-rotund or 

 reniform ; peridia double ; the outer rather thick, calcareous, 

 yellow, or yellowish white, the inner thin, yellowish ; capillitium 

 containing numerous irregular calcareous granules ; columella 

 none ; spores deep violet, 11-13 M* covered with minute spinules. 



This singular species occurs not rarely upon the bark of 

 fallen twigs, upon bits of straw or grass-stems lying undis- 

 turbed upon the ground. In such a position the Slime-mould 

 covers, as with a sheath, the entire substratum. The outer 

 peridium, especially its upper part, is entirely evanescent ; our 

 Fig. 3 shows the sporangia with upper outer peridium want- 

 ing. Not rare in summer and autumn. 



New England, New York, Pennsylvania, Ohio, Wisconsin, 

 Illinois, Iowa, Colorado, Nicaragua. 



6. PHYSARUM CONGLOMERATUM (Fr.~) Rost. 



1803. Spumaria granulata Schumacher, Saell., II., p. 196, No. 1419. 



1803. Spumaria minuta Schum., l-c. 



1829. Diderma granulatum Schum., Fries, S. M., III., p. lio. 



1829. Diderma minutum Schum., Fries, I.e., p. III. 



1829. Diderma conglomeratum Fries, I.e., p. in. 



1875. Physarum conglomeratum (Fr.) Rost., Man., p. 108. 



1892. Physarum rostafinskii Massee, Mon., p. 301 . 



1894. Physarum conglomeratum Rost., Lister, Rlycetosoa, p. 58. 



