Wednesday, 1 August 2018

Botanical finds this summer

Botanical activity over the last couple of months has been generating a lot of records and some fantastic finds. Activity has included two recording meetings organised by myself, an 'official' BSBI field outing to Nettlebed Common, as well as numerous other formal and informal recording meetings and other kinds of survey undertaken by local botanists. As it is about time that I posted something, I thought I would blog about some of the highlights.

The biggest surprise of the season (so far) is the double re-appearance of the nationally scarce Althaea officinalis (marsh mallow) in the county, with one site at Otmoor and the other by the Thames near Shiplake. Usually a plant of brackish marshes at coastal sites, A. officinalis was reported by Druce as appearing in a ditch at Long Meadow near Iffley/Oxford in the 1830s, and was more recently recorded as a casual from the Oxford tip. Where these newly recorded plants could have come from is a mystery. The Otmoor plant appeared a few years following the cutting of a hedge by a ditch on the RSPB reserve, and could have appeared from buried seed. Perhaps more plausibly as it is growing by a footpath, it could have been accidentally introduced from a visiting birder (it also grows at RSPB Minsmere). If it were an introduction, it seems odd that it should appear simultaneously with another plant at the other end of the county, but then it has never been known from Otmoor and is the habitat at either site right?

Thursday, 12 July 2018

Keys to grasses in Oxfordshire



Above: Ruth's multi-access key to the grasses of Oxfordshire developed using the Field Studies Council's Tomorrow's Biodiversity software. Below: Ruth's guide to grasses on iNaturalist.

Local botanist Camilla Lambrick has asked me to advertise some really great resources put together by herself and Ruth Ripley to aid with the identification of grasses in the county. Camilla says:

"Have you ever been frustrated that the grass you keyed out only grows in Shetland, or you have forgotten which a lemma is? Now, like buses, not one but three new keys to the grasses of Oxfordshire are available, developed by Ruth Ripley and illustrated with clear pictures:
  • The simplest to use of the three keys is the one on iNaturalist, available as a tablet or mobile app.  In this key you can choose easy features and instantly see photos of all the possible species. If you click on a photo you will find more information and photos.
  • A second online but more complex multi-access type key uses the Field Studies Council Tomorrow's Biodiversity software, available as a test version. This key gives a wide choice of features to compare together. This key illustrates the possibilities of the software — if you find it useful and would like it developed further please tell us!
  • A conventional dichotomous key by Camilla Lambrick can be found here. This key uses more technical terms, but it has a glossary.
None of the three keys are fully complete with recent introductions and cereal crops, but we hope to add to them. We would welcome your feedback and photos. Please email Ruth or Camilla.

Good hunting!"

Monday, 21 May 2018

Spring Atlas recording

May is always a very exciting time of year, and in the few weeks since I last posted there have been two Atlas recording meetings which I have organised, several ad hoc outings of my own, and I have had records from other botanists out recording themselves. I therefore thought I'd share some of the interesting findings from this early part of the season. If you've sent me records or participated in recording events and would like to see how your contribution has added to Atlas progress in the county, then I have updated the interactive Atlas map. I find this a useful tool for targeting my own recording and tracking progress and will update it every week or so.

The target areas for the last couple of my meetings have been rather underwhelming, Tusmore Park (SP53) this last Sunday being very sterile, and Fringford (SP62) two weeks ago also uninteresting. However, without much to keep one in a square there is the opportunity to range more widely and collect a greater number of records from a larger area. Beyond Tusmore on Sunday, we found many nice grassland plants along the A43, with Anthyllis vulneraria (kidney vetch), Briza media (quaking grass), Hippocrepis comosa (horseshoe vetch) and Lithospermum officinale (common gromwell) all new to the Oxon part of SP53. Also new to the Oxon part of the hectad was Carex distans (distant sedge), an uncommon plant of floodplain meadows and fens, found here by a carp pond by the brook that forms the boundary with Northants. It is also a plant of saltmarshes, and within the pond was a very surprising saltmarsh species, Bolboschoenus maritimus (sea club-rush), a county first. It may have been planted, but it is a very unusual choice of planting! It has been known from brackish marshes inland in other parts of England, such as at Marcham in VC 22, but never in VC 23. Salt-loving plants in Oxon are confined to the edges of salted roads, and indeed along the A43 we found the under-recorded halophytes Cochlearia danica (Danish scurvy-grass), Pucinellia distans (reflexed saltmarsh grass) and Spergularia marina (lesser sea spurrey).

Monday, 23 April 2018

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 6th? Please email me if you'd like to join us.