218 THE NORTH AMERICAN SLIME-MOULDS 



ii. Calyculus minute or none; nodes prominent, 



11. C. microcarpa 

 B. Sporangia more or less marked with purple or violet tints. 

 a. Purple or violet throughout. 



1. Net poorly developed . . . . 12. C. violacea 



2. Net well developed. 



i. Meshes regular and the nodes distinct, 14. C. elegans 

 ii. Meshes and nodules irregular . 13. C. purpurea 

 h. Purple tints confined chiefly to plasmodic granules on the calcy- 

 ulus and stipe. 

 Net with nodes well expanded. 



i. Stipe short, not more than double the sporangium; net 

 and calyculus both well developed 9. C. piriformis 

 ii. Stipe many times the sporangium, weak, 



15. C. languescens 

 iii. Stipe slender, sporangium copper-colored, 



16. C. cuprea 



1. Cribraria argillacea Pers. 



Plate XII., Figs. 12, 13; Plate XVII., Fig. 1. 



1791. Stetnonitis argillacea (Pers.) Gmel., Syst. Nat., II., 1469. 

 1796. Cribraria argillacea Pers., Obs. Myc, I., p. 90. 



Sporangia dull ochraceous-olivaceous, globose, nearly 1 mm. in 

 diameter, sessile or short stipitate, closely gregarious or crowded, 

 the peridial walls at maturity smooth, shining, except above, long 

 persistent, obscurely reticulate, with irregular thickenings which at 

 the apex at length present the appearance of an irregular, coarsely 

 meshed net without nodal thickenings; stipe very short, stout, erect, 

 reddish brown, spore-mass ochraceous, spores by transmitted light 

 pale, spinulose, 5-6 /t. 



This species stands just on the border-line between the tubiferas 

 and the genus now before us. While on the one hand it possesses 

 many characters such as the habit, form of sporangium, which are dis- 

 tinctly tubuline, on the other it shows in the upper peridial wall defi- 

 nite reticulations which suggest Cribraria. In freshly formed sporangia 

 the reticulations are barely visible in the crown; later on they are 

 more manifest, until, as spore-dispersal proceeds ; the cribraria char- 

 acters come out with sufficient distinctness, and in empty sporangia 

 the reticulations may be seen to affect the entire peridial wall. The 



