Tpie Myxomycetes of Eastern Iowa. 157 



numerous longitudinal plications. Capillitium well developed, 

 with abundant and irregular angular calcareous nodes. Spores 

 black, spinulose, .009-.011. 



Not common, on weather-beaten rails and stumps. Easily 

 recognizable by the elegant white stipe which sometimes per- 

 sists long after the fruit has been distributed by the winds. 

 August — October. 



60. Pkysarum contextum, Per soon. Plate IX, Figs. 3 



and 3^. 



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

 reniform. Peridia double; the outer rather thick, calcareous, 

 yellow, or white, the inner thin, yellowish. Capillitium con- 

 taining numerous irregular calcareous granules. Columella 

 none. Spores deep violet, .011-.013, 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. 



61. Physarum sinuosum, BuJUard. Plate VIII, Figs. 6 



and 6a. 



Sporangia distinct or plasmodiocarpous, the plasmodiocarp 

 creeping in long vein-like reticulations or curves, laterally 

 compressed; sometimes distinct and crowded, always sessile. 

 Peridium double; the outer thick, calcareous, fragile, snow- 

 white; the inner delicate, the dehiscence by longitudinal fis- 

 sure. Capillitium strongly developed with abundant white 

 calcareous granules. Spores smooth, dull violet, .ooS-.oop. 



