Marasmius capillaris is a species of agaric fungus in the family Marasmiaceae. A saprobic fungus, it produces fruit bodies (mushrooms) that grows in groups on decaying oak leaves in North America. The caps on the mushrooms are convex and then centrally depressed with radial furrows, measuring in diameter. The wiry, shiny stems are thin (less than 1 mm thick) and up to long. Its spore print is white, and the spores are smooth and pip-shaped, measuring 7âÂÂ11 by 3âÂÂ5 üm. The mushrooms somewhat resemble Marasmius rotula, but are smaller and darker in color.