246 



Mycetozoa of North America 



sporangia red or reddish. 



Sporangia cylindrical or ovoid, flesh-colored ; 

 capillitium marked with a loose spiral of 

 flat-topped cogs or spines. 

 Sporangia red, subcylindrical or ovoid; cap- 

 illitium marked with cogs and half-rings. 

 Sporangia flesh-colored, cylindrical or ovoid, 

 small; threads of the capillitium slender, 

 marked with transverse ridges and minute 

 spines. 

 Capillitium centrally attached, almost or quite free 

 from the cup. 

 Network of mature capillitium expanding but 

 not drooping. 

 Sporangia red; capillitium marked with cogs 



and spines. 

 Sporangia copper-colored ; capillitium marked 

 with cogs, spines, and ridges, often ar- 

 ranged to form partial or complete spirals. 

 Network of mature capillitium becoming much 

 elongate and drooping. 

 Sporangia yellow; sporangial wall evanes- 

 cent above. 

 Sporangia gray; sporangial wall evanescent 



above. 

 Sporangia red; sporangial wall persisting 

 above as small plates attached to the 

 capillitium. 

 Sporangia yellowish green. 

 Cup at length dividing nearly to the base into rounded 

 lobes. 



4, A. carnea 



7. A. denudata 



8. A. insignis 



9. A. incarnata 



10. A. stipata 



11. ^. nutans 



12. A. magna 



13. A. Oerstedtii 



14. A. virescens 



15. A. occidentalis 



1. Arcyria ferruginea Sauter, Flora 24: 316. 1841. 



Arcyria macrospora Peck, Rapt. N. Y. State Mus. 34: 43. 1883. (N. Y. 



B. G. no. 12253, type material.) 

 Heterotrichia Gabriellae Massee, Mon. 140. 1892; Macbr. & Martin, Myxo- 



mycetes 275. 1934. 

 Arcyria nodulosa Macbr. N. A. Slime-Moulds ed. 2. 252. 1922; Macbr. & 



Martin, Myxomycetes 268. 1934. 



Plasmodium rose-red or cream-colored (Lister). Total height 

 1 to 2 mm. Sporangia stalked, crowded, obovoid or short- 

 cylindrical, 0.7 to 1.3 mm. high, 0.3 to 1 mm. broad, orange-red 

 or red, rarely yellow; cup of sporangium even, shining, funnel- 

 shaped or nearly flat, marked with round-meshed reticulation on 



