Marasmius sasicola produces mushrooms that have convex caps from in diameter featuring folds or striations. The caps do not expand or flatten with age, and are dry and dull. The cap surface is covered in tiny grains which vanish as the mushrooms age. The caps of young mushrooms are coloured light brown, but paler at the cap margin; as they mature, the caps become paler, approaching white when fully matured. The very thin, smooth
stem measures between in length by thick. It connects to the centre of the cap, and is a dark brown to black colour.
Mycelial cords cannot be seen at the base of the stem, which anchors itself into the
substrate. The white
gills can be adnexed (attaching to the stem by only part of their depth) to adnate (attaching by their full depth). They are not at all crowded, with between 6 and 8 separate gills, all of which reach the stem. Each gill is up to broad, though it is thinner at the edge. The mushrooms have a very thin layer of whitish
flesh up to thick. The tough but flexible flesh lacks any odour or taste.
Microscopic characteristics Marasmius sasicola produces colourless, ellipsoid
basidiospores of between 8 and 10 by 4 to 6
micrometres (μm). The spores have no ornamentation, are not
amyloid and have thin
cell walls. In his examinations, Takahashi did not observe any
basidia, but he did describe the club-shaped basidioles (immature basidia) which measured from 18 to 26 by 6 to 10 μm. The tightly packed cheilocystidia (
cystidia on the edge of the gill) form a sterile edge to the gill, and there are no pleurocystidia (cystidia on the face of the gill). The
pileipellis, the top layer of the cap, forms a
hymeniderm, a cell structure reminiscent of the
hymenium on the gills. This is made up of club-shaped cells measuring between 2 and 8 by 7 to 10 μm, with reddish-brown, smooth cell walls up to 1 μm thick. The
stipitipellis, the outermost layer of the stem, is made up of cylindrical hyphae measuring from 3 to 6 μm in width, which run parallel to one another. They have featureless brown cell walls measuring up to 1 μm thick, and the septa (the walls separating individual cells) have
clamp connections. The flesh in the cap is made up of irregularly arranged cylindrical
hyphae from 5 to 15 μm wide. They stain a dark reddish-brown in
Melzer's reagent or
Lugol's solution. The flesh in the stem is made up of hyphae which run down the stem and measure 4 to 11 μm in thickness. The smooth cell walls are colorless, but again stain a dark reddish-brown in Melzer's reagent or Lugol's solution. The septa have clamp connections.
Similar species Marasmius subconiatus, known from Sri Lanka and Indonesia, is somewhat similar to
M. sasicola. It can be differentiated as its stem does not enter the substrate, and the gills differ. In
M. subconiatus, the gills are orange, and sport cheilocystidia which are pale yellow. ==Habitat and distribution==