The Myxomycetes of the Miami Valley, Ohio. 



sporangial wall, . loosely branched and forming no evident 

 net-work, the surface even, minutely warted or spinulose. 



a. Wall of the sporangium not thickened. 



10. Dianema. Capillitium of nearly straight smooth 

 threads running from base to top of sporangium. 



b. Wall of the sporangium with an outer layer of minute 

 scales and granules. 



11. Perichaena. Sporangia more or less depressed, 

 roundish, or more commonly polygonal and irregular, dehis- 

 cent in a circumscissile manner. 



12. Ophiotheca. Plasmodiocarp terete and more or less 

 elongated, bent and flexuous, sometimes annular or reticu- 

 late, irregularly dehiscent. 



V. ARCYRIACEAE, Sporangia stipitate, rarely sessile ; 

 capillitium of slender tubules repeatedly branching and ana- 

 stomosing to form a complicated net-work of evident meshes. 



a. Capillitium proceedifig from numerous points of the spo- 

 rangial wall. 



13. Lachnobolus. Tubules of the capillitium quite 

 variable in thickness, the surface minutely warted or spinu- 

 lose. 



b. Capillitium issuing from the interior of the stipe. 



14. Arcyria. Capillitium without any free extremities. 



15. Heterotrichia. Capillitium with numerous free 

 extremities. 



VI. TRICHIACE^E. Capillitium of slender tubules, sim- 

 ple or branched ; the surface furnished with continuous 

 ridges, which wind around the tube in a spiral manner. 



a. Capillitium of loiig, slender tubules, arising from the base 

 of the sporangium or issuing from the interior of the stipe. 



17 



