SUMMARY1.A new species ofCladochytriumhas been isolated in uni-fungal culture on dechlorophyllized corn leaves and non-water-proof cellophane, and in pure culture on 0.5 and 3 per cent plain agar.2.The development and structure of the fungus has been described.3.The specific namecrassumhas been proposed for this new species because of its coarse rhizomycelium.