Dyer's Mazegill

Phaeolus schweinitzii (Fr.) Pat.

1 Observations

2 weeks ago Last Observed

The Dyer's Mazegill (Phaeolus schweinitzii) is a large, velvety bracket, round or fan-shaped and often wavy, with concentric bands of orange, yellow and rusty brown. The pore surface is sulphur-yellow to citrine and darkens to reddish-brown when handled. It usually sits on a short, thick, bulbous or cylindrical stem, and the flesh is soft and moist when fresh. Old brackets dry out, turn dark brown and lose their colour.

It is an annual parasite that causes brown butt rot, mainly at the base of pine and other conifers, and sometimes appears from buried roots a little away from the trunk. It is common and widespread in the UK, and fruiting bodies can be found in any month of the year.

The all-yellow Chicken of the Woods (Laetiporus sulphureus) usually grows on hardwoods and lacks a velvety, banded cap. Onnia tomentosa is also similar, but is duller and has setae under the microscope. The Dyer's Mazegill is regarded as inedible and may be harmful, so it should not be eaten. Infected trees may be structurally unsafe.

Spore Print

Season

Native

unknown

Distribution

Common and widespread everywhere

Habitat

Parasitic on conifers, in particular Pinus, rarely on deciduous wood

Etymology

Phaeolus comes from Greek, with a prefix meaning dusky or dark and a diminutive ending, so roughly "somewhat dusky". This fits the dull brown colour of the ageing fruiting body. The epithet schweinitzii honours Lewis David von Schweinitz, the American botanist and mycologist, who studied this fungus. The common name refers to its use as a dye source, giving yellows, oranges and browns.

Associates

Pinus

Fruiting Body

The bracket is undulating, with a wavy surface and margin, and shows concentric zones of different colours running out towards the edge. The zoning is clearest on fresh specimens, with a brighter yellow margin, and it fades to dull brown as the fruiting body dries and ages.

Cycle	annual
Colour
Width	10 - 30 cm

Pores

The pores are 1-2 per mm, wide enough to see easily with the naked eye. They are irregular, and neighbouring tubes sometimes merge to give a few larger, maze-like pores. They bruise reddish-brown when touched and darken to brown with age.

Colour
Bruising

Tubes

The tubes are up to 1.5cm deep, forming a distinct layer beneath the cap flesh. They are greenish-yellow and often run down onto the stem.

Colour

Flesh

The flesh is soft and moist when fresh, a little spongy to the touch. It dries out and becomes hard and corky as the fruiting body ages.

Colour
Odour	Pleasant
Taste	Sour, acidic

Macrochemicals

KOH turns the flesh and cap surface black, often passing through a cherry-red stage in young specimens. KOH preparations also release yellow to orange pigment.

Spores

Smooth, ellipsoid to slightly ovoid and inamyloid, appearing hyaline to pale yellowish in KOH. The spore print is white.

Colour
Type	inamyloid
Size	5-7 x 3.5-4.5 μm

Microscopic Features

Hymenial cystidia are reported as cylindrical, thin-walled and smooth, with rounded or slightly swollen tips, and hyaline to brownish in KOH. No setae are present, which separates it from Onnia tomentosa.

Confirmed

Unconfirmed