APHOTOMARINE

An educational resource dedicated mainly to the photography
and diversity of marine life that can be found in coastal waters
and intertidal areas of Great Britain and Ireland by David Fenwick.

A-P-H-O-T-O Wildlife Stock Image Library
Dilsea carnosa, Red Rags, galled by unknown alga, Streblonema? - Skilly, Cornwall, 24.04.20. (Algal galls)
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Galling agent - alga?
Dilsea carnosa
- gall - macro image of -1

Galling agent - alga?
Dilsea carnosa
- gall - macro image of -2

Galling agent - alga?
Dilsea carnosa
- gall - macro image of -3

Galling agent - alga?
Dilsea carnosa
- galls - macro image of -1

Galling agent - alga?
Dilsea carnosa
- galls 1

Galling agent - alga?
Dilsea carnosa
- gall 2

Galling agent - alga?
Dilsea carnosa
- gall / 0.1mm division rule 1

Galling agent - alga?
Dilsea carnosa
- gall squash / fungal hyphae 1

Galling agent - alga?
Dilsea carnosa
- gall squash / fungal hyphae 2

Galling agent - alga?
Dilsea carnosa
- gall squash / fungal hyphae 3

Galling agent - alga?
Dilsea carnosa
- gall / transverse section 1

Galling agent - alga?
Dilsea carnosa
- Dilsea carnosa in-situ 1

These approx. 1.5mm dia. galls were found on on Red Rags or False Dulse, Dilsea carnosa, in a deep pool on the lowershore at Skilly, near Newlyn, Cornwall, 24.04.20.

Galling agent - alga?
Dilsea carnosa
- with gall dropped out ? 1

Galling agent - alga?
Dilsea carnosa
- with gall dropped out ? 2

Galling agent - alga?
Dilsea carnosa
- with gall dropped out ? 3

The above three images likely represent the gall once it has dropped out, the images do not fit with the fungus Mycaureola dilseae which is decribed as having a white inner ring shading to green then red of the Dilsea. The specimen above was found at Tavis Vor, Mousehole, Cornwall. 26.04.13.

The galls were looked at microscopically and were transverse sectioned and squashed to further investigate their cause. Dilsea carnosa is known to suffer necrotic lesions caused by the bysidiomycete fungus Mycaureola dilseae, Professor E.B. Gareth Jones has studied specimens of this gall and he did not find a fungus but an alga in its tissues.

Could the alga Streblonema be causing these galls?

Thanks to Professor E.B. Gareth Jones and Prof. Michael Guiry for their help and advice on this page.

Red Rags or False Dulse Dilsea carnosa hyperplasia alga algae algal Streblonema Gall images
The main objective of this website is in furthering environmental awareness and education through the medium of photography. To increase awareness and access to the wildlife of the region and help
people find and identify it. Sometimes the difference between species is obvious but many species can only be determined by observing microscopic characteristics that are specific to any one species.