The Myxomycetes of Eastern Iowa. 151 



litium is concolorous, in strong contrast to the dark black 

 spores. It is pretty hard to prove that some of the capillitium 

 branches are free, and consequently hard to see any reason 

 for the existence of this genus. The spores measure .0105 

 and are very slightly roughened. August. 



PHYSARELLA, Peck, 



Peridia stipitate, cup-shaped, furnished with calcareous 

 granules, the base, and hollow pseudo- columella persisting 

 after the fall of the spores. Capillitium made up of pale fila- 

 ments accompanied by four layers of spiniform tubes hori- 

 zontally radiant; tubules with lime granules. Spores globose, 

 smooth, brown-black. 



51. Physarella mirabilis. Peck. Plate Vlil, Figs. 4, 4a 

 and 4^. 



Sporangia stipitate, above sub-infundibuliform, slightly 

 fibrillose or squamulose, yellowish-rusty; the base and false 

 columella persistent. Stipe equal or scarcel}" conoid, rusty- 

 brown. Capillitium of delicate filaments, here and there 

 thickened and anastomosing, some of the tubes spiniform, 

 extending horizontally between the peridial walls. Spores 

 smooth, globose, brownish-black, .ooS in diameter. 



This species has been found here but once, on dead birch 

 bark. The sporangia are variable in form. Some are stalked, 

 cup-shaped, as described; others are entirely sessile, irregular, 

 flabellate, or even spherical. The calcareous thickenings are 

 bright yellow, especiall}* the large very conspicuous spine-like 

 structures which constitute the trabecular portion of the capil- 

 litium. The sporangia are usually large, some as much as 

 one-eighth of an inch high. 



P. inirahiUs seems to be so far the only species and appears 

 to be the same as Tilmadochc oblonira, B. and C. = Trickam- 

 fhora ohlonga, B. and C. in Grcvillca^ 1S73. 



