Gymnosporangium sp. - Gymnosporangium

Hawthorn (Crataegus) are the alternate host for two gall-causing rust species in the genus Gymnosporangium.  Aecia are produced on reddish swollen spots on leaves, fruits, petioles and shoot.  The aecia have long fringes (peridia) so the aecia have a pale brown whiskery appearance.  The aecial stages are very similar and species cannot be distinguished from field photos in this stage.  

The telial stages are on Juniper, the primary host - see gallery pages for Gymnosporangium confusum and Gymnosporangium  clavariiforme.  However, the two species are able to produce aecia in areas where there are no infected junipers. 

See above.

See above.

Fairly frequent and widespread in Britain.

Fairly frequent in Leicestershire and Rutland.