A wander down the Dene

Yesterday’s walk took me to a nature reserve a little further from home than usual.  Castle Eden Dene is one of a series of deep valleys, cut by streams running through the soft Permian limestone of NE England down to the North Sea.  Depending on whom you believe, the valley is either named for its ancient Yew trees (‘Eden’ evolving from ‘Yoden’ or Yew Dene) or its name comes directly from the old English word ‘Idun’ for a spring.  The dene is a Site of Special Scientific Interest and National Nature reserve, one of the largest areas of semi-natural woodland in this part of the world, with many plants indicative of ancient woodland.  The deeply-shaded valley floor drips with ferns and mosses but also some interesting flowering plants, including Bird’s nest orchids, which I’ve yet to see.

The stream bed of upper reaches of Castle Eden Burn

Of late, Castle Eden Dene has been more Martyn’s patch than mine.  Castle Eden Burn flows only seasonally down the middle of the valley, making it an interesting habitat for a freshwater biologist (at least when there is water present!)   On Saturday we walked much of the length of the burn in the stream bed only having to dodge puddles occasionally, at least in the upper part of the valley, despite heavy rain on the preceding days. We were looking for the type of amphibious plants you might expect to find at the edges of a seasonal river – mint, watercress and brooklime – but found no trace of any till we reached where the river forms a sort of freshwater lagoon and marsh at the dene mouth.  The steep, rocky sides of the valley and periodic episodes of very high flow seem to have prevented the accumulation of the type of organic matter needed to allow these plants to establish themselves.

All is not lost for a botanist, though.  A little further from the stream there is plenty of interest; Giant bellflowers, several of the less common St John’s worts, the ubiquitous Enchanter’s nightshade and Common figwort.

Clockwise from top left: Campanula latifolia, Hypericum hirsutum, Circaea lutetiana and Scrophularia nodosa

I’ve always wondered where Enchanter’s nightshade got its name but, according to Geoffrey Grigson’s The Englishman’s Flora, there is no suggestion the plant was used in spells and enchantments until the earliest 16th Century herbals were published.  Around then, it somehow became associated with a herb used by Homer’s witch, Circe, to change the crew of the Ulysses into Pigs and acquired its generic name, Circaea.

Figwort’s scientific name, Scrophularia, derives from the old medical practice of ‘Doctrine of Signatures’. The knobbly roots were thought to indicate that figwort could be used to treat piles (also known as ‘the fig’) or swollen throat glands. Incidentally, Lesser celandine is sometimes known as figwort for the same reason, though I have no idea whether either herb has any actual efficacy!   

There are also Broad-leaved helleborines, Epipactis helleborine, with a range of flower colours on the woodland floor – they seem to be doing particularly well this year. Surrounded by a cloud of wasps inebriated after supping from flower cups or hypochiles brimming with fermenting nectar, some of the pollinia in the flower spike on the right, below, seem to have gone adrift rather than having been transported to another flower on the head of a pollinator.  Long-headed wasps such as Dolichovespula are the most efficient pollinators of these flowers; other insects can get at the nectar but are the wrong shape to transfer pollen – maybe this is what happened here.

Epipactis helleborine

Further downstream, the burn looks increasingly like a full-time stream, so we were forced onto the bank to continue our walk.  Whilst the burn passes under the coast road in a long culvert, the path climbs steeply up to the road and back down the other side, assuming you make it across the road in one piece!  Crossing the A1086 on foot is hairy, to put it mildly, not least because the view around the corner is obscured by tall vegetation – maybe one place where the council really should be trimming the road verges.  

When the path drops down again to the burn the wooded valley opens out suddenly into a floodplain meadow, with grasses held well in check by abundant, parasitic Red bartsia.  Where the burn finally disappears beneath a pile of accumulated mine spoil at the top of the beach we find a single, rather scrawny brooklime, Veronica beccabunga.  The meadow itself, the short turf above the beach and the dry open slopes around, are alive with insects of all sorts – Teasels, Hemp agrimony and Wild marjoram in particular attract both bees and butterflies and stridulating grasshoppers provide the backdrop to our picnic.  It seems a world away from the wildwoods of the upper dene.

Origanum vulgare and Dipsacus fullonum at Denemouth

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