264 THE MYXOMYCETES 



g. Spores 7-8 fx 6. A . incarnata 



g. Spores 10-12 y. h . 



h. Capillitium with numerous node-like expansions 7. A. nodulosa 



h. Capillitium without node-like expansions 8. A. ferruginea 



i. Sporangia globose or subglobose; capillitium only slightly 



elastic j 



i. Sporangia ovate or cylindrical ; capillitium more elastic k 



j. Capillitium marked with blunt spines, warts and trans- 

 verse bands 9. A . pomiformis 



j. Capillitium with close-set rings 10. A. annulifera 



k. Pale bluish green becoming greenish drab 11. A. glauca 



k. Cinereous or yellowish / 



k. Red or flesh colored m 



/. Sporangia separate 12. A. cinerea 



I. Sporangia clustered 13. A. digitata 



m. Flesh colored 14. A . carnea 



m. Rose colored, small; stipe short 15. A. insignis 



m. Red, weathering to brown, robust; stipe long 16. A. denudata 



1. Arcyria magna Rex 



Proc. Acad. Nat. Sc. Phila. 1893 : 364. 

 PI. XVII, Figs. 446, 447, 448, 449. 



Sporangia densely aggregated, forming clusters of greater or less 

 extent, sometimes reaching several centimeters in either direction, 

 tawny gray or ashen, cylindric, narrowing a little above, when ex- 

 panded reaching a length of 5-10 mm. or more, stipitate; peridium 

 iridescent, evanescent except the small shallow cup-like base, the 

 calyculus; stipe 1 mm. long, weak, pale brown or reddish, tubular, the 

 channel filled with plasmodic masses; capillitium gray or drab, very 

 slightly attached to the bottom of the calyculus, far expanded, forming 

 a loose-meshed net, the threads regular, cylindric, coarsely sculptured 

 with rings, half-rings, cogs, spines, etc. ; spores in mass dull gray, drab, 

 under the lens colorless, minutely spinulose or papillate, with few 

 papillae, 6-8 /x. 



This magnificent form resembles in habit and general appearance, 

 save color, A . nutans. The capillitium is, however, very different both 

 in the sculpture and in the more delicate markings of the threads. 

 Doctor Rex has pointed out the lack of reticulation on the capillitium 

 and calyculus. The color is also diagnostic. A roseate variety seems to 

 occur with the present form. This is A. magna var. rosea Rex, and 

 appears to agree with the type in all respects save color. The capil- 

 litial threads are remarkable for their graceful slenderness, regularity, 

 and symmetry. 



Regarded by Lister as a form of A . cerstedtii, from which, however, 



