Abortiporus biennis

(Bull.) Singer

A well-formed mature fruiting body on a shadow stump of English oak in Pitsea, Essex.
Peripheral to the stem of a Swedish whitebeam in Basildon, Essex
Archetypal rosette forming at the base of whitebeam in Basildon, Essex
Tiered rosette between buttresses of poplar in Basildon, Essex
Cross-section showing flesh and tube layer on an ash stump in Wickford, Essex

A well-formed mature fruiting body on a shadow stump of English oak in Pitsea, Essex.
Peripheral to the stem of a Swedish whitebeam in Basildon, Essex
Archetypal rosette forming at the base of whitebeam in Basildon, Essex
Tiered rosette between buttresses of poplar in Basildon, Essex
Cross-section showing flesh and tube layer on an ash stump in Wickford, Essex
Developing and guttating rosette at the base of poplar in Basildon, UK.
A mature and over-mature duo of rosettes at the base of bird cherry in Laindon, UK.
The aberrant upper surface of a developing rosette on an ash stump in Wickford, UK.
Aberrant growths on upper surface of mature rosette on a shadow oak stump in Pitsea, UK.
Partially aborted disfigured rosette at the base of whitebeam in Fryerns, UK.

Common name

Blushing Rosette

Often found on

Species within the Rosaceae family.

Sometimes found on

Other deciduous broadleaved trees.

Location

Found at and around the base of the tree – often away from the stem. Also found on (shadow) stumps.

Description

Annual . Tough. Incredibly varied appearance. Begins as a white mass that exudes red liquid – often with pores on the upper surface. May develop into a rosette and turn a dark red-brown on the upper surface – pore layer remains white and bruises pinkish. May also simply become a very large mass of pores. Growth will consume blades of grass and twigs. Flesh white. Spore white. Can have long stipe (‘stem’) buried in soil.

Confused with

Ganoderma australe (in early stage – brown flesh), Perenniporia fraxinea (in early stage – usually yellow and flesh beige); Rigidoporus ulmarius (in early stage – orange-cinnamon tube layer ).

Significance

Attributed to a selective white rot of the wood. No research has been undertaken on the pathogenicity of this fungus. Presence on standing trees indicates root damage and dysfunction. May be associated with decline, in cases where colonisation is extensive and the crown of the tree is sparse.