Spiders and Gentians

Today was a gorgeously sunny moment to have a short walk on Ashdown Forest. Our local heath hosts a nice range of habitats, in which some rare and beautiful species can be found, and they were the focus of our walk.

The primary purpose of the walk was to see one of the Forest’s iconic rare flowers, the Marsh Gentian (Gentiana pneumonanthe), though we could also appreciate many of the common heathland plants, and, guided by Evan and Stephen, some of the diverse range of our local spiders.

Starting off with the common plants, we paused to note the differences between Common Gorse (Ulex europaeus) and its diminutive relative Dwarf Gorse (Ulex minor). The latter has recently come into flower, and the stems are much finer than the very familiar bigger one. Furthermore, if you gently take hold of a stem of Dwarf Gorse and take it in your hand, you can pull your clasped hand along its length without doing yourself an injury, which is not something you can do with Common Gorse.

Picture of Dwarf Gorse (Ulex minor)

Dwarf Gorse (Ulex minor)

It didn’t take long before the spider populations were coming to our attention. Initially revealed by the sheet webs catching the light, a very abundant species on and around the gorse was Linyphia triangularis with its humpbacked shape, waiting upside-down on its web.

Picture of Linyphia triangularis

Linyphia triangularis

Then, the youngest member of our party found the first of the gentians, nestling in among some Cross-leaved Heath (Erica tetralix). These were slightly outside the area in which we found them with the Sussex Botanical Recording Society last year. It is also instructive to see their national distribution; they really are quite a rare species, and one which requires suitably grazed wet heath to survive, which is now an extremely scarce habitat, so it is important that its few remaining areas don’t get encroached by gorse, long grass or (worse) trees.

Map of the distribution of Gentiana pneumonanthe

Map of the distribution of Gentiana pneumonanthe

Picture of Cross-leaved Heath (Erica tetralix) and Marsh Gentian (Gentiana pneumonanthe)

Cross-leaved Heath (Erica tetralix) and Marsh Gentian (Gentiana pneumonanthe)

In the end, we found over 50 spikes of the Gentian, and we certainly didn’t manage to cover the whole area in which they are known to occur. Some of the groups of plants were definitely not recorded last year, so we’ll certainly be submitting the records for this season, and will try and get back in the next few days to record the rest of the patch. It feels like there are more than last year.

Picture of Marsh Gentian (Gentiana pneumonanthe)

Marsh Gentian (Gentiana pneumonanthe)

At this point we got a bit damp, since we were in a bit of a bog, though it wasn’t too severe. Unsurprisingly, there were several bog plants, such as some nice Sphagnum mosses, such as S. compactum and the rather wonderfully wine-red S. capillifolium ssp. rubellum.

Picture of Sphagnum compactum

Sphagnum compactum

And, this late in the season there were also some spikes of Bog Asphodel (Narthecium ossifragum), looking rather different from the yellow-flowered beacons they display earlier in the year. However, I don’t think any of us noted any of the common insectivorous plant that we often see in bogs on the forest, Round-leaved Sundew (Drosera rotundifolia).

Picture of Bog Asphodel (Narthecium ossifragum)

Bog Asphodel (Narthecium ossifragum)

There were lots of spiders to divert us too, and having some arachnophiles in the group helped us considerably. There were two common ones, the first of which was the red form of the Four-spotted Orb Weaver (Araneus quadratus), which typically spends its time on the edge of its web.

Picture of Four-spotted Orb Weaver (Araneus quadratus)

Four-spotted Orb Weaver (Araneus quadratus)

This is unlike is relative, the familiar Garden Spider (Araneus diadematus) with its distinctive cross on its back, which is more often found in the middle of its web.

Picture of Garden Spider (Araneus diadematus)

Garden Spider (Araneus diadematus)

Evan also found a cocoon of Cheiracanthium erraticum, of which the British Arachnological Society says:

It is most easily found in early summer by looking for the retreat constructed from two or three leaves, or grass heads, stitched together to make a retreat which will hold the female and egg-sac. Later in the year, immature specimens, which already show the reddish median stripe on the abdomen, can be found in small silk cells on plant stems

Picture of Cheiracanthium erraticum

Cheiracanthium erraticum

The range of webs we saw was enormous. In addition to the ‘traditional’ webs of the Garden Spider, there were also bits of gorse covered in these mite webs, which were almost encased in thread.

Fine mite webs on Gorse

Fine mite webs on Gorse

There were various funnel webs, and a range of sheet webs, including this massive sheet made by the Labyrinth Spider (Agelena labyrinthica).

Web of Labyrinth Spider (Agelena labyrinthica)

Web of Labyrinth Spider (Agelena labyrinthica)

Finally, on the way back to the car park, we noted other common heath plants, such as Tormentil (Potentilla erecta), Mat-grass (Nardus stricta) and (in damper spots) Sharp-flowered Rush (Juncus acutiflorus), as well as more of the blue-flowered Devil’s-bit Scabious (Succisa pratensis), which was quite frequent in this part of the Forest.

Picture of Tormentil (Potentilla erecta)

Tormentil (Potentilla erecta)

Picture of Devil's-bit Scabious (Succisa pratensis)

Devil’s-bit Scabious (Succisa pratensis)

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