Polhill Bank

After doing a bit of College work, some shopping, calling in at the Parish Office and painting some external windows, I took Monty for his afternoon walk up to a bit of the North Kent Downs I have never been to before, Polhill Bank.

The M25 cuts through the Downs here, but Polhill Bank also faces the Darenth Valley as well as the Gault Vale looking South towards Sevenoaks, so you get the contrast of peaceful rural views delighting the eye with the roar of traffic in your ears. The easiest way to access the reserve is to park in the A224 layby on the other side of the M25 cutting and cross the footbridge over the motorway towards the reserve, looking down on the rushing traffic of London's orbital motorway 70 - 80 feet below your feet.

A quick path through the beech-woods on the skeletal soils of the crest leads you through the reserve gate and out onto the steep Bank itself, with the view opening out in front of you:

Just as I arrived a brownish raptor with a white rump and a long tail flew over. It looked like a female or immature Hen Harrier, Circus cyaneus, but of course it couldn't have been - wrong place, wrong season!
There was still a good variety of plants in flower, including the Devil's-bit Scabious, Succisa pratensis with its undivided leaves, although I usually associate this plant with wetter soils. Here is the one large patch I saw with one female Common Blue nectaring on one plant:

It is interesting to compare the Devil's-bit with a true Scabious, the Small Scabious, Scabiosa columbaria, a characteristic flower of the chalk downs in Kent. The outer flowers are much larger than the central ones, and the stamens that you can see are clearly balanced on their central filaments. Note the greyish spider surprisingly well camouflaged against the blue background,

A commoner flower across the small reserve as a whole is the Eyebright, Euphrasia species, the tiny whitish flowers of which are everywhere you look, and a fantastic flower when you look at them close up:

and here is the ubiquitous Wild Basil, Clinopodium vulgare, with its dense whorls of flowers which however only open several at a time,

and another Labiate, the beautiful and very common Marjoram, Origanum vulgare, with its much lighter flowers in tighter packed terminal panicles, each with their beautiful projecting stamens, and the aromatic leaves with much less impressed veins (seen in the original photos). If you click on the photo and expand it up, you can just see a thrips or thunderfly on one of the flowers at the top right of the panicle:

This is the Dwarf Thistle, Cirsium acaule, a plant nearly completely specific to calcareous grassland,

and this is the odd-looking Carline Thistle, Carlina vulgaris, which may look strange but with its purple sheen, still very attractive to bees:

while this is Common Soapwort, Saponaria officinalis, a common plant on different soils in the region,

Here is the low growing Lesser Trefoil, Trifolium dubium, creeping along the ground,

and the even lower growing Hoary Plantain, Plantago media, with its attractive pinkish flowers the only plantain pollinated by insects as opposed to wind-pollinated

This is the Common Knapweed, Centaurea nigra, but here on these poor soils it grows to a fraction of the size I normally see it in the woods, The composite flower-head however remains unmistakeable:

and here is the Perforate St Johns Wort, Hypericum perforatum, with the characteristic black dots on the petal edges just visible if you click and expand the picture,

and finally I couldn't resist putting in a last flower, the Rock-rose, Helianthemum nummularium, although its a rather blurry picture, it is still so fundamentally characteristic of these poor chalky soils.

However on several of the Kent Wildlife Trust chalkland reserves all this diversity is uncder threat from this one yellowish invasive grass, Tor-grass, which threatens to out-compete and overwhelm the floristic diversity of the chalk downland, unless the grazing is very carefully and flexibly managed:

Although its nearly the end of the butterfly season, and the day was very breezy, the open ground was packed with Meadow Browns, Maniola jurtina,

some generally rather small Gatekeepers, Pyronia tithonus. This one is slightly unusual in that it appears to have only one white spot on the dark eye.

and the occasional Common Blue, Polyommatus icarus, like this female, (postscript - it is possible that this is a fairly faded female Chalkhill Blue, Polyommatus coridon, perhaps indicated by the slight indication of lines running across the outer white fringe of the forewing)