Trentepohlia abietina is an alga that forms bright orange or orange-brown patches on tree trunks.
View under the microscope of the reddish, short filaments of swollen or elliptical cells of Trentepohlia umbrina. © P V York
The orange-red pigment protects the alga against intense sunlight.
This alga is easy to find in the more humid westerly parts of the British Isles.
Its relatives - including Trentepohlia iolithus - form unsightly red streaks on buildings.
Trentepohlia is the most common algal genus in lichens.
Trentepohlia abietina forms felt-like patches on tree trunks. Find out what gives the patches their texture.
Trentepohlia abietina usually grows on tree trunks. But where?
Trentepohlia abietina is widely distributed. Find out how this alga reproduces.
Get reference information for Trentepohlia abietina.
Distinctive orange coloured covering of the Trentepohlia abietina on trunks of two ash trees near Toys Hill, Kent.© D M John
Close view of the orange felt-like covering on tree bark of Trentepohlia abietina.© M D Guiry and F Rindi
Reddish colouration caused by the crustose covering Trentepohlia umbrina on the bark of an apple tree in Scadbury Country Park, Bromley, Kent.© D M John
The reddish discoloration of the wall of a suburban house in Galway City, Ireland caused by Trentepohlia iolithus. It is known locally as ‘red rust’.© M D Guiry and F Rindi
Orange-coloured patches of Trentephohlia abietina on a tree trunk along with grey-coloured crustose lichens.
Close view of red-coloured patches of the crustose Trentepohlia umbrina - sometimes grows with T. abientina and confused with it.
Professor David John
Department of Botany
"My attention has been drawn to Trentepohlia abietina by lichenologists and amateur naturalists who have noticed, in recent years, an increase in the number of orange-red tree trunks in south and south-eastern England. It is only possible to speculate on the reasons for the increase in Trentepohlia - perhaps decreased pollution, short-term climatic change - until such time as a systematic research study is undertaken."