Plants and animals of Pointfield

Small, dark brown ophalinoid with a deeply sunken umbilicus and inturned rim; surface slightly fibrous in inner part; disc lightening in colour towards edge and striate in outer part. Gills strongly decurrent; sides paler than disc but with a dark red-brown outer edge, especially in lower part; arranged as primary and secondary cycles. Stem also dark brown and smooth without lichenised base. Cap diameter 8 mm, stem length 11 mm. Very short, fine hyphae at base penetrating between sand grains.

Spores 5.8-7.2 x 3.6-4.4 um (mean = 6.2 x 3.9 um, N =20); average Q = 1.58; ellipsoidal with no germ pore and smooth walls; translucent in KOH. No cystidia found. The spore dimensions are significantly smaller than those quoted for O. pyxidata and the cap rather darker with striations more marginally confined.

Growing on weather surface of a sandstone block in close association with the moss Tortula muralis in pond rockery.