Poplar field cap / Spring / Summer / Autumn  / Edible

The Poplar Field cap (Agrocybe cylindracea), also known as the Poplar Mushroom or Willow Mushroom, is an edible delight that thrives on decaying wood, particularly around poplar, willow, and other hardwood trees. With its smooth, tan-brown cap, creamy gills, and robust stem, this mushroom is a joy to spot during foraging trips, especially in autumn and spring.

Favoured for its mild, earthy flavour and versatile culinary uses, the Poplar Fieldcap is a fantastic addition to soups, stir-fries, and risottos. However, proper identification is key, as it shares its habitat with some inedible and toxic lookalikes.

In this post, we’ll guide you through identifying the Poplar Fieldcap, where to find it, and tips for preparing it to make the most of this delicious wild mushroom.

Scientific Name

Cyclocybe cylindracea, Agrocybe cylindracea, Agrocybe aegerita

Common Name

Poplar fieldcap or Pioppino in Italy where it is very popular. Also Velvet pioppino and black popular mushroom.

Family

Strophariaceae  

Habitat and season

To find poplar field caps your best chance is to find its habitat which as the name suggests is with Poplar trees, Black poplar in particular.  Saprophytic causing white rot growing off dead poplar stumps, can also look to be growing out the ground but it in fact growing off the wood beneath the ground, also occasionally grows off willow which is the same family and in damp woods with other deciduous trees. .

Growing in dense clumps

Can be a common find in the UK as long as you are in the correct habitat. More common in central and southern parts of Europe.

From late spring through to early autumn, can grow multiple times in a year from the same area so it’s worth revisiting to check if they have re fruited. 

Identifying Features of the Poplar field cap

Cap 

Mid brown and slightly wrinkled at first looking much like little bread buns, the shape when young is hemispherical/ convex like a sphere cut in half, later flattening out with age. As they mature the edges become lighter colour and split, this is a key characteristic., 4-10cm across.  The cap surface is very matt and uneven looking with pits. 

Stem

Can be variable, 5-15cm long cream in colour becoming darker with age. Persistent ring close to the cap on a cylindrical stem, often tapering towards the base, rarely straight.

Gills

Initially cream turning turning mid brown as spores mature, adnate to slightly decurrent and crowded.

Flesh

Firm, white/ cream, with no colour changes, can be brown at the very base of the stem, flesh is more fibrous in the stem.

Smell:

Strong and pleasant

Spores

Brown spore deposit

Edibility/culinary notes of the Poplar Field Cap

A delicious edible mushroom considered a delicacy, widely cultivated. 

Has a rich nutty taste with firm crisp flesh and rarely full of grubs. Stems can be a little tough which you many want to discard but still edible. Incredibly versatile and popular culinary mushroom.

Also very nutritious containing B2, B3 and B5 also potassium, biotin, iron, selenium and anti-microbial properties.

Poplar field cap Could Be Confused With

No poisonous look-alikes that appear in dense clusters so be sure to tick off this key feature.  But could easily be confused with other field caps mentioned below. May possibly be confused with Agaricus sp but these have free gills which are pink when young

These two below are considered an advanced ID so not recommended for beginners. 

Spring fieldcap- Agrocybe precox appears in spring, likes to grow in piles of woodchip, has a prominent mycelial cord looking like white roots. Smells less pleasant, only just passable as an edible as it can be quite bitter. Appears in groups rather than dense clusters.

Wrinkled fieldcap- Agrocybe rivulosa Again in groups rather than dense clusters, on piles wood chip or mulch. Smell is milder. The cap has wrinkles in folks like river valleys. 

Caution and known hazards 

Not in the fruiting body itself but only with mis-identification but this species is quite beginner friendly. 

Extra Tips and Fun Facts

Regarded as one of the best fungi to recycle dead wood stumps.

The Romans and Greeks were believed to be the first to cultivate the Poplar mushroom.

In China they are used in traditional medicine to help reduce symptoms of nausea, fevers, and headache.

Source

Nature-first.com

Edible mushrooms by Geoff Dann 

Fungi of temperate Europe by Thomas Laesson and Jens H.Peterson