206 THE MYXOMYCETES 



date 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 — "in 

 vetustissimis plenariae destructioni proximis arborum truncis" — is 

 pertinent for all the species save one. Rotten coniferous wood seems 

 to be preferred, but frondose wood is by no means refused. Rotten 

 oak forms a not infrequent substratum. 



The major part of the following key and a considerable part of the 

 treatment of the species is based on the work of Miss Eunice Lovejoy, 

 presented as a thesis at the University of Iowa in 1931. 



KEY TO THE SPECIES OF CRIBRARIA 



a. Net obscure, fugacious; sporangia sessile or short-stipitate; 



densely crowded 1. C. argillacea 



a. Net persistent; sporangia stalked; gregarious or scattered b 



b. Ochraceous or brown c 



b. Orange, red or purple q 



c. Caly cuius lacking, or, if present, very small or represented 



by ribs. (See also Nos. 6, 14) d 



c. Calyculus well developed. (See also Nos. 4, 5) g 



d. Free ends lacking in net, or few e 



d. Free ends usually numerous / 



e. Moderately large, 0.3-0.7 mm. in diameter; nodes flat- 

 tened 2. C. splendens 



e. Small, under 0.4 mm. in diameter; nodes thickened 3. C. microcarpa 



f. Connecting threads of net single; granules ochra- 

 ceous 4. C. didydioides 



/. Connecting threads often parallel in twos or threes; 



granules dark brown 5. C. intricata 



g. Nodes expanded h 



g. Nodes thickened * 



h. Net light ochraceous, meshes small, with no free ends . . 6. C. minutissima 

 h. Net dark brown, meshes large, with free ends 7. C. atrofusca 



i. Nodes flat and angular j 



i. Nodes rounded o 



j. Sporangia small, under 0.4 mm k 



j. Sporangia larger, over 0.5 mm tn 



k. Copper colored; meshes large; nodular granules pale 8. C. cuprea 



k. Dark brown, with dark granules I 



I. Deep reddish brown; spores 5-6.5 n 9. C. languescens 



I. Nearly black; spores 9/x 10. C. oregana 



m. Spores reticulated 11. C. dictyospora 



m. Spores spiny or roughened n 



n. Dusky; margin of calyculus dentate; free ends few 12. C. piriformis 



n. Yellow-brown; margin of calyculus perforated; free ends 



numerous 13. C. macrocarpa 



