Agrocybe rivulosa: The Ultimate Mushroom Guide

About The Agrocybe rivulosa Mushroom

Agrocybe rivulosa is rare a species of mushroom in the genus Agrocybe. It is a relatively large mushroom, with a stem of 5 to 10 cm, and a cap that reaches 4 to 10 cm across. The color of the cap ranges from yellow to pale orange-brown. It grows tall with a whitish fleshy stem. It has been eaten and is reasonably tasty with no obvious toxicity.

In some field guides, this mushroom is recorded in the family Bolbitiaceae.

Other names: Wrinkled Fieldcap.

Agrocybe rivulosa Identification

1. Cap

   4 to 10 cm across, hemispherical becoming broadly convex or flat; the pale ochraceous surface develops radial wrinkles linked by a network of cross-veins.

2. Gills

   Adnate; initially creamy-grey, turning grey-brown as spores mature.

3. Stem

   5 to 10 cm long and 1 to 1.5 cm dia.; hollow; tapering slightly towards the apex; white, turning a pale creamy-ochre with age; persistent, thin pendulous stem ring.

4. Spores

   Ellipsoidal, smooth, 11.5-12 x 7-8µm; with a distinct germ pore.

5. Spore Print

   Brown.

6. Odor and Taste

   Not distinctive

7. Habitat & Ecological Role

   Saprobic, on large groups or tufts on woodchip piles and deeply-mulched flowerbeds.

8. Similar Species

   Agrocybe praecox, which occurs in spring and early summer, often grows in woodchip mulch; it is typically smaller and usually has a darker cap.

Agrocybe rivulosa Taxonomy & Etymology

This species was first recorded and described in 2003 as Agrocybe rivulosa by Dutch mycologist Marijke M. Nauta and published in Persoonia.

Agrocybe rivulosa and a minority of other fieldcap fungi do not occur in open fields; nevertheless, the generic name Agrocybe is derived from Agro-, of fields, and -cybe, head or cap.

The specific epithet rivulosa is a reference to the wrinkled grooves that descend like rivulets from the centre of the caps.