Flammulaster rhombosporus is a very small, tan colored mushroom which grows in eucalyptus debris in the spring.  It has a powdery cap, brown spores and orange gills.   It's edibility is unknown.

In Oakland, it has been found in Joaquin Miller Park.

Flammulaster rhombosporus by Alan RockefellerFlammulaster rhombosporus by Alan RockefellerFlammulaster rhombosporus by Alan RockefellerFlammulaster rhombosporus spores and cheilocystidia 1000x by Alan Rockefeller