Blushing Rosette

Abortiporus biennis (Bull.) Singer

1 Observations

2 weeks ago Last Observed

The Blushing Rosette (Abortiporus biennis) is a tough, stalked bracket that often forms overlapping, rosette-like clusters, 8-15 cm across. The upper surface is smooth to finely velvety and radially wrinkled, creamy white to reddish-brown. The flesh-pink pores are maze-like and the white flesh turns blood-red when cut or damaged, which gives the fungus its name. It has an unpleasant smell and a thick, clay-pink stem buried in the soil.

It grows on buried roots of broadleaved trees, usually at the edges of woodland and in parks, and fruits from summer through to winter. It is widespread and common in southern England and less often recorded further north.

The reddening flesh and pores, and the rooting habit, make it fairly distinctive. Other pale polypores with similar rosettes, such as Meripilus giganteus (Giant Polypore), have finer pores and blacken when handled. The Blushing Rosette is too tough to be of interest as food and is best treated as inedible.

Spore Print

Season

Native

non-toxic

Distribution

Widespread and common in southern England

Habitat

On buried roots on soil. In parks and woodland edges

Etymology

Abortiporus comes from the Latin abortus (failed, miscarried) and the Greek poros (pore), referring to the pores, which are often irregular and poorly formed. The epithet biennis is Latin for 'lasting two years'. This is misleading, because the fruiting bodies are annual; the name dates from Bulliard's original description as Boletus biennis.

Fruiting Body

The upper surface is smooth to finely velvety, with radial wrinkles running out from the stem towards the margin. The overlapping caps form a loose rosette.

Cycle	annual
Colour
Width	8 - 15 cm
Bruising

Pores

The pores are small and maze-like, numbering 1-3 per mm. They redden when bruised.

Colour
Bruising

Tubes

The white tubes are short, 2-5 mm deep.

Colour

Flesh

The flesh is tough, but softer towards the outside of the fruiting body. It turns red when cut.

Colour
Odour	Unpleasant
Taste	Mild

Macrochemicals

The flesh and pores redden on cutting or bruising, which is a diagnostic field character. KOH gives no reaction to a pale brown reaction on the flesh.

Spores

Spores are smooth and ellipsoid, about 4.5-6 x 3.5-4.5 µm, colourless in KOH and inamyloid. The spore print is cream. Chlamydospores (thick-walled, rounded resting cells about 5-10 µm) may also be present and in some collections are the only spore-like cells found.

Colour
Size	4.5-6 x 3.5-4.5 μm

Microscopic Features

Cystidia are thin-walled, smooth and cylindrical to spindle-shaped, about 20-50 x 4-7 µm, sometimes with constrictions that give a 'chess bishop' outline. They are colourless in KOH and are described as gloeocystidia in some sources.

Confirmed

Unconfirmed