The Myxomycetes of Eastern Iowa. 123 



SUB-GENERA. 



I. Capillitium adherent to the margin of the persistent cup-like 



base of the peridium, Clathroides. 



11. Capillitium closed below and adherent to the peridium but 



slightly and at but a single point, Arcyrella. 



Sub-genus Clathroides, {Mtcheli) Rostafinski. 



12. Arcyria cinerea, [Bnlh'ard). Plate II, Figs. 3 and 3^. 



Peridia gregarious, stalked, elongate ovate; stipe simple, 

 straight, smooth, fuscous. Capillitium and spore-mass pale 

 ashy grey; tubes of the capillitium warty or spinulose. 

 Spores smooth, .006-.008, colorless. Plasmodium bluish-white 

 in very delicate reticulations. 



This species although world-wide in distribution occurs 

 sparingly with us — has in fact been collected but once, on 

 decaying stumps of Tilta americana^ " bass-wood." The 

 sporangia after the expansion of the capillitium are long per- 

 sistent, the capillitium itself assuming a definite and character- 

 istic outline, with beautiful tracery-like reticulations. The 

 spores extend down into the stipal cavity. July, 1886. 



13. Arcyria punicea, Per soon. Plate II, Figs. 5 and 5«. 



Peridia crowded, commonly stalked, more or less ovoid, 

 lustrous. Stipe straight, of varying length, spirally plicate. 

 Color of all parts various in different cases, generally flushed 

 with a roseate or carmine tinge, sometimes ])rilliant. Capil- 

 litium thread equal, flattened, adorned with thickenings in 

 form of rings or half-rings. Spores smooth, .006-.007. July 

 — December. 



This is one of the commonest species of the whole list. 

 World-wide in distribution it seems to occur in any given 

 locality with a constancy and persistence that bespeaks thor- 

 ough adaptation to environment and present terrestrial con- 

 <iitions generally. I find it uniformly upon fallen stems of 

 Populus and Tilta^ possibly because in our dry season these 



