Hymenogaster olivaceus

A small hypogeous fungus barely reaching 3 cm in its final developmental stage. The basidioma is initially white, turning brown at maturity, and finally adopting greyish-olive tones, hence the specific epithet olivaceus.

It may appear at virtually any time of year under various broadleaved trees, typically on calcareous soils.

The specimens studied here were found in mid-June in Orduña (Bizkaia), growing in small clusters barely peeking above the bare ground of a road cutting under Quercus faginea on limestone. An additional fruiting was observed in September of the same year.