GRAMINEOUS CEOPS. 



97 



was first described by the late Eev. M. J. Berkeley, 

 F.R.S., in the Journal Linnean Society (vol. xiii. p. 175). 

 This fiingus occurs chiefly in the South and South-west 

 of England, and appears only to attack certain grasses 

 growing on calcareous and siliceous soUs. The reason for 



Fig. 38. — ISABIA PUCIFORMIS OP GRASSES 



A. A grass infested with the fungus (a). 



B. End of a fongns tuft (a) with eonidia (spores). 



C. Gonidia. x 670 diam. (Zeiss' E., 4oc.) 



the growth of I. fuciformis on certain grasses growing 

 on the previously mentioned soils, may be due to iihe fact 

 that both calcareous and siliceous soils contain (as a rule) 

 smaller percentages of iron oxide than argillaceous soils. 



