The Stachybotry alternans fungus is a cellulolytic saprophytes. Under natural conditions it well develops celluloserich substrates; straw, hay, grain, various weeds, and plant remains. It attacks cotton, hemp articles, wood, sackcloth, paper. On straw and grain it forms a black powdery, easily removable coating. Taken for mycological examination are suspected specimens of straw (weat, rye, oats) threshing residues, more seldom hay (of cereals) and oats. Straws affected by the fungus are examined with a magnifying glass. The heaviest accumulation of the fungi to observed on the nodules of the straw where one can see a black powdery coating of spores. The dark coating is scraped off and placed into a drop of a 50% aqueous glycerol solution on a slide, covered with a cover glass, and examined microscopically at low magnification. Darkly coloured conidiophores and the fallen spores of the fungus will be seen in the visual field.