Cottisford

The 2018 recording season is truly upon us, and Sunday was the first of several Atlas 2020 recording meetings I will be organising this year. The target was far-flung Cottisford, an area in the north of the county I had never been to before, and I was joined by four other keen botanists for a delightful day botanising in glorious spring weather. I had identified this square (SP53V) as a target for recording using the interactive Atlas 2020 coverage map available here. Although the tetrad had around 150 taxa recorded it still had a low recording rate indicating there was much else to find, so the aim of the meeting was to focus on species and habitats not covered by previous records: as these were focused on the Cottisford Pond Local Wildlife Site (LWS), there was plenty other ground to cover. Notable plants to look out for included Astragalus glychyphyllos (wild liquorice), last seen in 1993, and Carex elata (tufted sedge), last in 1968. Read on to learn whether we found either!

We started off in the churchyard in the village, St Mary the Virgin, where we had the usual lawnmower-tolerant species of unimproved churchyard grassland such as Plantago media (hoary plantain). There was a single rosette of Dactylorhiza fuchsii (common spotted orchid) and an abundance of flowering Luzula campestris (field wood-rush), an understated spring beauty. Making out of the village for the area where the Astragalus was last recorded we came upon a few patches of flowering Rancunulus auricomus (goldilocks buttercup) in a hedgebank. Further along were scraps of limestone grassland with an abundance of Cirsium eriophorum (wooly thistle) and a few plants of Lithospermum officinale (common gromwell), which was new the to square. Also new was Hypericum maculatum (imperforate St John's wort), relatively scarce in Oxon, and further up the lane we found the sought-after Astragalus, much to our delight. There were a mere five small tufts of this species growing in a rather unprepossessing verge by a farm track.

The next few hours were spent wondering along footpaths picking up records from a variety of habitats. Two large fields of Linum usitatissimum (cultivated flax) provided many arable weeds, welcome as these are usually scarce so early in the year. The company disbanded after hunting out the plants of Cottisford village, where we found rather few garden escapees, and I headed out alone to the last recorded location of Carex elata. I was quickly disappointed as this was an arable field, but diving into the woodland in the shallow valley below I immediately found around 20 tufts in a spring-fed swamp - as Carex elata had been known from only one site in the county this was clearly a significant find! I continued to find further plants, keeping count until I came across a large area of flooded woodland that supported thousands of individuals, and I was puzzled as to how this plant had been missed here for fifty years! Several large tussocks were also growing in Cottisford Pond itself.

Right: a tussock of Carex elata growing in Cottisford Pond. Below left: its wet woodland habitat. Below right: a diagnostic feature of C. elata is the leaf-sheaths, which split into many ladder-like fibres.

The woodland around Cottisford Pond had plenty of other good plants to add to the list, with a range of ancient woodland and wetland species. Neottia ovata (twayblade) and Valeriana dioica (marsh valerian) were both new to the tetrad, the latter a surprise as I had never known this uncommon and threatened species to ever turn up at a new site or to grow in woodland. To the south above the valley, the woods on the hill and the small area of Shelswell Park within the tetrad added a good deal of further interest. This area supported acid grassland, a very rare habitat in Oxfordshire, and I was able to re-record Campanula rotundifolia (harebell), Cirsium acaule (dwarf thistle) and Galium saxatile (heath bedstraw) as well as add Carex caryophyllea (spring sedge), Filipendula vulgaris (dropwort) and Veronica officinalis (heath speedwell) new to the tetrad. The glacial sand and gravel deposits across this part of the county, from Hardwick north-east to Finmere and Mixbury, would certainly be worth further survey.

After a bit more back-and-forth along footpaths to try to pick up extra species, I eventually returned to Cottisford carrying a satisfyingly full recording card. Together the meeting bumped the tetrad up to a total of 300 taxa, recording 260 taxa and making 287 records, greatly exceeding my expectations. It was particularly gratifying to find so many new native species and few aliens for a change, and of course to re-record a number of locally important plants. Who knows what we will find in a forthnight's time at the next meeting on May 6^th? Please email me if you'd like to join us.