Cribraria 187 



Var. simplex Rex, Bot. Gaz. 17: 202. 1892. 



Physarum caespitosum Peck, Rept. N. Y. State Mus. 26: 75. 1874. (N. Y. 



B. G. nos. 5486, 7971, 11254, type material.) 

 Perichaena caespitosa Peck, Rept. N. Y. State Mus. 31: 57. 1879. 



Sporangia shortly cylindrical, closely compacted, sessile, usu- 

 ally in a single layer, rarely free and short-stalked. 



Type LOCALITY: Germany. 



Habitat: On dead coniferous wood. 



Distribution: The typical form and var. simplex are widely 

 distributed throughout the United States and Canada, and not 

 uncommon. 



Illustration: Lister, Mycetozoa ed. 3. pi. 137. 



Some developments superficially resemble certain phases of 

 Tubifera ferruginosa, but may be distinguished by the spores and 

 plasmodic granules. Var. simplex is intermediate between the 

 typical form and Cribraria argillacea, and connecting forms are 

 found. L. effusa is often found nearby or associated with 

 C. argillacea. 



Genus 27. CRIBRARIA Persoon, Neues Mag. Bot. 1: 91. 

 1794. 



Sporangia globose or piriform, stalked; sporangial wall either 

 forming a cup in the lower half or reduced to a basal disc, con- 

 tinued above as a net of slender threads more or less expanded and 

 thickened at the nodes, membranous and evanescent in the meshes 

 of the net. Dark plasmodic granules present in the cup and nodes 

 of the net. 



Type species : Cribraria rufescens Pers. 



The genus is a difficult one. A number of the species are so 

 closely connected by numerous intermediate forms, that many of 

 the collections are practically indeterminate, particularly if the 

 material is in poor condition; many developments mature im- 

 perfectly; the colors for sporangia and spores, as given, are for 

 fresh, perfect specimens, as the colors alter with age in many 

 cases; and the size and arrangement of the plasmodic granules, 

 while useful in diagnosis, are not always constant. 



Sporangia ochraceous, yellow, or brown. 



Cup and net present, but junction imperfectly defined 

 in fresh material; nodes when present flattened. 

 Sporangial wall thickened below, persisting as a 

 cup and merging gradually into a fragile, im- 

 perfect, irregularly meshed net. 1. C. argillacea 



