DHBlog009 · An article by Alex Mills
Alex Mills is a Vascular Plant Specialist at Natural England. Although not currently based in Dorset, he maintains a love for the county’s botanical treats. All images belong to Alex.
The recent Dorset Biodiversity Audit (2021) lists Valerianella rimosa (Broad-fruited Cornsalad) as extinct in the county. The first Dorset record for the species is George Stacey Gibson’s from the Isle of Portland (SY67) in 1843. The last was H.J.B. Brotherton’s from Chillbridge Farm, Wimborne (ST9802) in 1982. Between these dates it was recorded from 13 hectads. This loss mirrors the precipitous decline of V. rimosa in Britain during the second half of the twentieth century. However, news of Broad-fruited Cornsalad’s extinction in vc9 may have been a tad premature.
In June 2019, Billy Dykes and I were walking along on that dreamlike stretch of coast path between Winspit Quarry and St Aldhelm’s Head on the Isle of Purbeck. I was ahead, probably with some thought already on The Square & Compass, when observant and conscientious Billy asked ‘what’s this then?’, pointing at a small plant next to the path. I’d walked straight past it, thinking it another Valerianella eriocarpa (Hairy-fruited Cornsalad). which thrives in the area (common as muck, you might say…). Since we’d stopped, I thought we’d probably have a peek at the characteristic fruits of V. eriocarpa. However, we were confronted instead with the characteristic fruits of…something else. Photos were taken. Keys were scrutinised. Tentative identification was made. But it couldn’t be. Could it? The photos were duly sent to Dr Fred Rumsey who very kindly confirmed the determination. It was Broad-fruited Cornsalad.
Returning in May 2022, our target Cornsalad was not at its 2019 spot. Despite having just enjoyed ogling the ridiculous fruits of the Critically Endangered (CR) Scandix pectin-veneris (Shepherd’s-needle), this was disappointing. This disappointment only lasted a grand total of roughly 50 metres, however: further along the path, heading west, more V. rimosa was found.
What can we take from this? First, excitement. V. rimosa is Nationally Scarce and is listed as Endangered on both the GB and England Vascular Plant Red Lists. It’s thought to have been present in Britain since the Iron Age and, in Dorset, was present in post-Roman deposits from an archaeological excavation near Poundbury in the 1970s. Its status as an archaeophyte, and so not native, should not erase our concern for its conservation. The fate of V. rimosa is emblematic of that for arable plants, often termed arable weeds, in Britain more widely. We could have all sorts of fun getting distracted debating the semantics of the terminology, but I won’t. Instead I’ll note that arable plants are some of the most vulnerable in Britain. The BSBI’s Threatened Plants Project (2017), which focussed on a selection of species associated with different habitats in Britain and Ireland, found that the most threatened species were those associated with arable land, such as Fumaria parviflora (Fine-leaved Fumitory), Glebionis segetum (Corn Marigold), Rancunculus arvensis (Corn Buttercup), and Torilis arvensis (Spreading Hedge-parsley). We cannot fail to be aware of the impacts of changes in agricultural practice and land use, and it may appear difficult to imagine a space for these plants in the current system. Excellent work by conservationists has been attempting to aid these arable plants, for example the Back from the Brink project’s Colour in the Margins, led by Plantlife. It’s also heartening to get the indication that V. rimosa can take advantage of situations if given a slight chance.
In the context of concerns over its survival as a Dorset denizen, the obvious question remains: was Broad-fruited Cornsalad popping up near St Aldhelm’s Head over the years, consistently or sporadically, and just missed or overlooked, or do the recent records represent a return from the soil seedbank? The species is fairly inconspicuous and, when spotted, requires a bit of scrutiny to arrive at an identification. Even then, uncertainty may remain and not everyone who looks at the plant may be able to check with experts to confirm the ID. That these Valerianellas were growing at a known location for V. eriocarpa may have led botanists to, as I initially did, assume it would be that flavour of cornsalad and walk on by. It’s not inconceivable, therefore, that our cornsalad was making an appearance throughout the years and going unnoticed. Poor thing. However, it is a well-trodden path, and if it had been appearing regularly over the years one would think it would have been spotted. It’s not actually known how long the seeds of V. rimosa can remain viable in the seedbank, but they have been conjectured to be long-lived (in excess of 30 years). Arable plants are often latently present in the seedbank – it’s one of their evolutionary traits which has enable them to exploit the niche presented by arable cultivation. So, it could have been lying in wait until congenial conditions were present. Perhaps the drought year of 2018 somehow facilitated its appearance in 2019? Resolving this question appears unanswerable. Both possible scenarios, or a mixture of the two, seem feasible.
In his article on the county’s extinct plants in the 1993 edition of Recording Dorset (which included V. rimosa) David Pearman urged botanists to go and see if the species could be refound. The return of Broad-fruited Cornsalad shows that for some species we should not give up hope but continue to keep the old eyes peeled. And that we should not be lazy botanists who make identification assumptions (thanks, Billy!).
Editor’s Note: I wonder how many other rare species have been missed in our hurry to get to the pub or just the car at the end of a day in the field? If you want to find out more about V. rimosa, Plantlife published a report back in 2008. You can download it here.