30 July 2013

Field trip to Loch na Sreinge


Our July midweek field trip took us along the String of Lorn from Lochavich House to Loch na Sreinge, where we were hoping to find Awlwort which was recorded there in 1990.

Scotch Argus butterflies were numerous on the way to the loch.  This one has an unusual green and purple iridescence at the front edge of the wings.  We also saw Green-veined Whites and a Dark Green Fritillary, and Cynthia spotted a Barred Straw moth.
 

Vapourer Moth caterpillars were about in numbers, on a remarkable variety of plants (often with feeding signs), including some up in the trees on an island close to the loch shore.

 

I thought this was the Goblet Waxcap (Hygrocybe cantharellus) but in fact it's the scarce H coccineocrenata, which I've never seen before and is a new vice-county record.  It seems to lack an English name but the Latin translates as Wavy-edged Scarlet Waxcap.

 

The loch was rich in aquatic plants.  This is Floating Bur-reed.
 

You can tell what's growing out in the deeper parts of a loch by looking at pieces washed up on the shore.  This is Perfoliate Pondweed.
 

The water level was very low.  Here the stems of Water Lobelia, originally upright, have become nearly horizontal as the water level dropped, and then grown vertically from the tips to hold the flowers clear of the water.  The tangled mass of red vegetation on the right is Alternate Water-milfoil.
 

Close-up of Water Lobelia flowers.  The leaf-rosettes on the loch floor can also be seen.  The blunt ends to the strap-like leaves distinguish them from other aquatic rosettes.

 

Various-leaved Pondweed, which has broad opaque leaves on the surface and narrow translucent leaves underwater.



This Horse Leech was making its way towards Julian as we sat eating our lunch at the loch edge.
 

Our target species Awlwort proved very elusive, and was finally spotted by Chris just as we were about to give up.  A single tiny plant with one flower and one fruit (the fruit is mostly hidden by the stem in the pic).  It normally has several but having to grow out of water due to the low loch level will have made things difficult.  The much larger leaf-rosettes of Shoreweed are around it in the pic, these were everywhere along the loch shore.

 

Bristle Club-rush, found by Chris in a wet area beside the track to the loch.


Water plants found at Loch na Sreinge

Callitriche brutia Narrow-leaved Water-starwort Well above current water level
Carex lasiocarpa Slender Sedge  
Carex rostrata Bottle Sedge  
Eleocharis palustris Common Spike-rush  
Equisetum fluviatile Water Horsetail  
Isoetes lacustris Quillwort Washed up
Littorella uniflora Shoreweed Very abundant.  Flowering due to low water level.
Lobelia dortmanna Water Lobelia Abundant
Menyanthes trifoliata Bogbean  
Myriophyllum alterniflorum Alternate Water-milfoil  
Nymphaea alba White Water-lily Leaf washed up.  Not seen on loch surface.
Potamogeton alpinus Red Pondweed Washed up
Potamogeton berchtoldii Small Pondweed Found once, perhaps overlooked elsewhere
Potamogeton gramineus Various-leaved Pondweed Plentiful near the island
Potamogeton perfoliatus Perfoliate Pondweed Washed up
Potamogeton polygonifolius Bog Pondweed  
Ranunculus flammula Lesser Spearwort  
Schoenoplectus lacustris Common Club-rush Forms large stands
Sparganium angustifolium Floating Bur-reed In bay formed by the island
Subularia aquatica Awlwort Scarce!

 

This photo by Julian shows well the difference between Water Lobelia rosettes and the narrower and more pointed Shoreweed rosettes.  Photo Julian Overnell.
 

A Golden-ringed Dragonfly.  We saw two or three of these, also several Large Red Damselflies and one Common Blue Damselfly.
Photo Sallie Jack.


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All photos and other content copyright Carl Farmer except where stated.