Abortiporus biennis

What You Should Know

Abortiporus biennis feeds on buried wood (roots, stumps) of dead trees and occasionally of conifers. It can also parasitize the roots of living trees. It eventually can develop a more typical-appearing rosette of caps and stems, but initially takes on several lumpy forms. It should ooze red droplets when the flesh is squeezed.

This mushroom occurs throughout many parts of Europe and North America where it grows as an amorphous mass of irregular maze-like pores exuding blobs of red-brown juice.

Other names: Bleeding or Blushing Rosette.

Abortiporus biennis Mushroom Identification

1. Ecology

   Saprobic on the wood of hardwoods and occasionally conifers; growing alone or gregariously around the bases of stumps and living trees; causing a white rot in deadwood and a white trunk rot in living wood; summer and fall (also winter and spring in warm climates); widely distributed in North America.

2. "Aborted" Form

   An irregular mass of exposed pore surface, with or without a clearly defined upper surface that is smooth and reddish-brown; ranging from singular and vaguely cup-shaped to clustered or nearly coral-like, with separated, individual projections; pore surface whitish to pinkish, bruising reddish to reddish-brown; pores angular to maze-like or irregular, 1–3 per mm; flesh tough, whitish to pinkish, when fresh exuding a pinkish to orangish liquid.

3. Cap

   5–15 cm across; roundish-to semicircular, kidney-shaped, or irregular in outline; plano-convex; finely to thickly velvety, or sometimes more or less bald; dry; light brown to reddish-brown or tan, with a pale margin; sometimes with concentric zones of brown shades.

4. Pore Surface

   Whitish, bruising and discoloring reddish or pinkish brown; pores appearing "stuffed" when young, later angular to maze-like or irregular, 1–4 per mm; tubes to 5 mm deep.

5. Stem

   When present 3–10 cm long; 1–3 cm thick; lateral; tapering to base; soft and spongy; fuzzy; brownish.

6. Flesh

   White to pinkish or pale tan; exuding a pinkish juice when squeezed; tough.

7. Spore Print

   White.

Abortiporus biennis Taxonomy and Etymology

In 1789, the French mycologist Jean-Baptiste François Pierre Briard described the species and gave it the binomial name Boletus biennis.

In 1944 German-American mycologist Rolf Singer gave this species the currently-accepted name Abortiporus biennis.

Abortiporus, the genus name, comes from the Latin Abortus- meaning arrested development (of an organism), and -porus, derived from ancient Greek and meaning a pore. The specific epithet biennis means biennial.

Abortiporus biennis Synonyms

1. Boletus biennis Bull.

2. Sistotrema bienne (Bull.) Pers.

3. Hydnum bienne (Bull.) Lam. & DC.

4. Daedalea biennis (Bull.) Fr.

5. Polyporus biennis (Bull.) Fr.

6. Phaeolus biennis (Bull.) Pilát

Sources:

Photo 1 - Author: Iskra Kajevska (Creative Commons Attribution-Share Alike 4.0 International)

Photo 2 - Author: AJC1 from UK (Creative Commons Attribution-Share Alike 2.0 Generic)

Photo 3 - Author: zaca (Creative Commons Attribution-Share Alike 3.0 Unported)