Nature Notes from Skye
(and occasionally other places)

Fri 5 - Mon 8 Aug 2005 (Part 3)

First, six gall-like things that were either decided against or were unidentifiable.

Enlarged bud on Betula pubescens   Distortion on Senecio jacobaea induced by Trupanea stellata

This enlarged Birch bud was at first thought to be the work of the Acalitus calicophythirus mite, but on examination under the microscope it was found not to be a mite gall.  Instead it contained a caterpillar, probably a Tortricid.

The deformed Ragwort flowers contained the larvae of the Tetriphid fly Trupanea stellata.  Although they are responsible for the mis-shapen flowers these are not true galls.

Aphid-induced distortion on Prunus spinosa   Fasciation on Thymus polytrichus

This leaf distortion on Blackthorn is also caused by aphids and is not a true gall.  Compare the aphid leaf-roll on Hawkweed from the previous page which is a true gall, according to the book.  It is very much a matter of opinion where to draw the line between galls and non-galls, but generally speaking the requirement for a gall is that it gives some benefit to the organism which causes it, rather than being an "unintended" side-effect of that organism's activities.

The second picture shows a fasciated form of Thyme, with normal green Thyme in the lower part.  The fasciated portion is deep red and has all parts smaller than the normal form and distorted.  This is not thought to be caused by any external organism.

Unknown red warts on Juniperus communis   Unknown leaf roll on Dryas octopetala

I found these tiny red warts on Juniper needles, and no-one knew what they were.  Am hoping to get an identification soon.  The red leaf-roll on Mountain Avens is also bit of a puzzle and is still being investigated.  Under the microscope it proved to have an erineum, but no mites were present.

The rest of the pictures on this page are of microfungi that grow on plants but do not cause galls.

Isothea rhytismoides on Dryas octopetala
  Puccinia cnici-oleracei on Cirsium heterophyllum

Puccinia cnici-oleracei on Cirsium heterophyllum

Mountain Avens again, this time with the fungus Isothea rhytismoides.  The other two pictures are the front and back of a leaf of Melancholy Thistle with the rust fungus Puccinia cnici-oleracei.  This may be the same thing as the mystery "gall" I showed on 2 Sep 2004.

Puccinia phragmitis on Phragmites australis   Puccinia obscura on Luzula multiflora s.s.

This rust on Reed stems and leaves is Puccinia phragmitis, which causes a gall when on its alternate hosts, Docks and Sorrels.  The rust on Heath Woodrush was identified as Puccinia obscura which causes a gall on its alternate host Daisy.

Uromyces anthyllidis on Anthyllis vulneraria   Septoria scabiosicola on Succisa pratensis

The rust Uromyces anthyllidis on Kidney Vetch, which forms brown spots with papery turned-up edges, and another fungus, Septoria scabiosicola, on Devilsbit Scabious.

The rest of the items on this page are unidentified.

Thymus polytrichus with unknown fungal(?) effect   Black spots on Alnus glutinosa

Pink and white discolouration on Thyme, and Black spots on Alder.  The latter was very numerous on some Alder trees and the area of leaf where the spots were was always yellowish.  Under the microscope they are slightly raised black glossy spots, typically say 0.3 mm diameter.  On the underside there is nothing except a very few of the same black spots, and the same yellowing.

Black wilt on Lathyrus linifolius   Black spots on dead leaf of Ammophila arenaria   Phyllonorycter rajella mine on Alnus glutinosa

Not often can a black wilt be said to be beautiful but I think this one on Bitter Vetch is rather fetching.  Middle pic is of black spots on a dead Marram leaf.  Under the microscope the spots are erumpent, they start off under the skin of the leaf and their edges remain there but their centres have burst through.  They're typically about 0.2-0.4 mm long but can be up to 0.8 mm long, and are all about 0.25 mm wide (perhaps the length variation is due to coalescing).  The final pic is of a leaf mine on Alder.  Later - this has to be the mine of the moth Phyllonorycter rajella.

There were other unidentified things but I'm drawing the line here, we must move on.  For some of the items found I may have other photos, specimens, grid refs etc if anyone is interested.  Time to get out into the field now and look for some of the new galls on Skye - particularly Little Black Puddings!

The remaining page of this Bettyhill section will show macro-invertebrates and macro-fungi - i.e. things that aren't regarded as diseases of something else!



All photos and other content copyright Carl Farmer