CRIBRARIA 217 



The genus Cribraria, as limited by Persoon, included all forms 

 in which the peridium is thin, evanescent half-way down, or entirely, 

 and in which capillitium, as Persoon regarded the case, is formed of 

 a network of reticulate threads surrounding the spores, Schrader 

 re-defined the genus; opposed Persoon's view as to the capillitial 

 nature of the net, and separated the genus Dictydiurn, but by imper- 

 fect limitations, — in fact, chiefly because of the more completely 

 evanescent peridium. Fries follows Schrader. Rostafinski first clear- 

 ly separated the two genera, and his classification is here adopted. 

 Nevertheless, after reviewing the subject entire one is more and 

 more inclined to appreciate the commendation of Fries; "Auctor 

 Schrader, qui insuper plurimas species detexit, et hoc et sequens 

 genus ita proposuit ut sequentes vix aliquid addere valuerint." 



As to the habitat of the cribrarias, the remark of Schrader is still 

 pertinent — "in vetustissimis plenarias destructionis proximis arborum 

 truncis" — for all the species. Rotten, coniferous wood seems to be 

 preferred, but the decayed logs of trees of other orders are by no 

 means refused. Rotten oak forms a very common habitat. 



Key to the Species of Cribraria 



A. Sporangia with spores ochraceous or brownish. 



a. Sporangia larger, .5 mm. or more. 



1. Net poorly developed, sometimes merely indicated, 



1. C. argillacea 



2. Net conspicuous, nodes expanded, not swollen. 



i. Calyculus reticulately thickened, ill-defined above, 



2. C. macrocarpa 

 ii. Calyculus with radiant lines or ribs; net small- 

 meshed; free ends none . 6. C. aurantiaca 

 iii. Net wide-meshed, calyx rufous . 4. C. rufa 

 iv. Calyx replaced by ribs . . 5. C. splendens 



3. Net conspicuous, nodules swollen. 



i. Net-threads simple; free ends many 



7. C. dictydioides 

 ii. Net-threads often parallel in twos or threes, 



8. C. intricata 



b. Sporangia small, less than .5 mm. 



1. Nodes not expanded . . . 3. C. minutissima 



2. Nodes well shown. 



i. Calyculus distinctly marked by radiant lines, nodes 

 round 10. C tenella 



