12 THE FUNGI WHICH CAUSE PLANT DISEASE 



Capillitium in part hyaline 

 Sporangium vaselike, or more or less tubu- 

 lar 



Opening irregularly 5. Physarella. 



Opening by a lid 6. Crateiium. 



Sporangia various, dehiscence irregular 

 CapiUitium evenly branched; the calca- 

 reous nodes small, fusiform 7. Tilmadoche. 



CapiUitium intricate 8. Physaium, p. 12. 



The species of Fuligo produce very large yellowish plasmodia 

 which change to yellowish or brownish aethalia. Some are credited 

 with damage similar to that of the preceding species.^* 



Physarum Persoon 



Sporangia plasmodiocarpous, sethalioid or distinct; the peridium 

 usually simple, sometimes double, irregularly dehiscent, more or 

 less definitely calcareous; capillitium a uni- 

 form irregular net, dilated and calcareous at 

 the nodes, adherent on all sides to the 

 peridial wall. 



P. cinereum (Batsch), Pers., the species 

 most commonly reported as injurious, forms 

 its tiny sessOe, gray sporangia in great num- 

 bers on living plants,*' ^'^ often smother- 

 FiG. 3.-Ph78arum *"S them. The peridium is lime charged as 

 sporangium. After are also the nodes of the capillitium. The 



"^ " ^' spores are brown or violet, and warty. 



P. bivalve F. has been noted as injuring young bean plants.^' 

 Dendrophagus globosus Toumey was reported by Toumey '' 

 as the probable cause of crown gall, but such relation is doubt- 

 ful (p. 36). It is said to be closely related to Physarum. 



