Rickenella swartzii is a tiny agaric that is pale grey to grey-brown. The cap centre (navel) is almost black while it is cream-coloured at the margin. The top of the stem is tinged dark violet. It grows in scattered trooping groups in lawns and other grasslands, typically with moss.

Cap initially convex and then expands to become nearly flat, occasionally having a central depression that gives it an infundibuliform (funnel-like) shape. The cap's margin is usually curved downward and is occasionally wavy. The colour of the cap is dark brown at the centre (disc) and transitions to a pale tan shade towards the margin. The flesh is cream-coloured and very thin. Gills pallid, deeply decurrent, fairly well-spaced, at first whitish, then cream-coloured. Stem rounded and mostly equal in width, with a slight enlargement at the apex. Its surface is similar to the cap, with a powdery texture (pruinose), particularly at the apex. As the mushroom ages, the stem becomes almost smooth (nearly glabrous). The colour of the stem ranges from dark vinaceous-brown to bluish-black at the apex, transitioning to a pale buff-orange shade below. There is no partial veil present. Spore print whitish.

Microscopic Features: The spores are elliptical in face-view, slightly inequilateral in profile, and measure approximately 4.0-5.5 (6) x 2.5-3.5 µm. They have a smooth surface, thin walls, granular contents, and a well-developed hilar appendage. The spores are inamyloid.

Rickenella swartzii on the mykoweb.com Web site.