The East Pit and the rare Moon Carrot

That sounds like a title of a children’s book, but a couple of weeks ago I went on an evening walk lead by members of the Wildlife Trust in an old chalk quarry in Cambridge and discovered a whole load of plants I’d never heard of or seen before, including the rare Moon Carrot. (In fact, until recently I didn’t know of the existence of the quarry or SSSI* in Cherry Hinton, just a couple of miles from the Cambridge City centre either.)

An evening Wildlife Trust guided walk in the East Pit, Cherry Hinton, Cambridge

Late to the party, due to waiting at the wrong entrance, a couple of us were quickly caught up to speed on species immediately visible. Wild thyme was the most obvious since its mauve flowers painted large areas of the quarry floor, but there was also Common Milkwort (Polygala vulgaris), Salad burnet (Sanguisorba minor), Mouse-ear Hawkweed (Pilosella officinarum), Mignonette (Reseda Lutea) and Bird’s-foot Trefoil (Lotus corniculatus).

Tapestry of chalk-loving wild flowers on quarry floor

The East Pit, which is where these photos are taken, is the larger quarry and was worked up until the 1980s, providing hard chalk and cement for the University Colleges. Taken over by the Wildlife Trust, re-profiling was carried out in 2009 on the base of the pit to form three gentle depressions. This process broke up much of the solid chalk surface and enabled wildflowers and grasses to spread and colonise the exposed chalk.

View of the East Pit from the South End, showing the three reprofile depressions

Trust volunteers report waves of colonisation taking place: This year the Kidney Vetch (Anthyllis vulneraria) is growing very strongly at the South end of the pit. Nothing has been deliberately introduced, so new species are blow-ins from the surrounding area.

The Pits support plenty interesting invertebrates too, including colourful Burnet moths  (whose caterpillars munch on the Bird’s-foot trefoil), glow-worms (seen in July) and this Eyed Hawk-moth:

Eyed Hawk-moth – Smerinthus ocellata

So here is a gallery of some of the lovely, delicate plants I’ve never seen before:

Centaury – Centaurium erythraea

Fairy Flax – Linum cartarticum. (Dreadful photo ‘cos the auto focus couldn’t find the tiny flowers)

Yellow-wort – Blackstonia perfoliata

Nodding or Musk thistle – Carduus nutans

Perforated St John’s wort – Hypericum perforatum

Rest-Harrow – Ononia repens

OK, I know this one…. but they were so posed

And finally, the rare Moon Carrot (Seseli libanotis), which only grows here and at two other locations in the country (Beachy Head, East Sussex and Knocking Hoe, Bedfordshire). Apparently, it gets its name because of the shape of its flowering head and some say because it glows in the dark. The umbel is rather a rather distinctive cauliflower-shaped. In the East Pit it is growing on the steep cliffs to the west, so I had to climb a bit to get this shot, hence the oblique angle.

Moon Carrot (Seseli libanotis)

Close-up of an immature umbel of the moon carrot

It is similar to wild carrot.

All in all, a good local discovery to have made and I plan to go back for the glow-worm count at the end of the month and maybe later for the bat evening.

* SSSI – Site of Special Scientific Interest

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