Are you overlooking Overlooked Sorrel (Rumex acetosa subsp. biformis)?

Email: paulbsbivcr4h12@gmail.com

I had never heard of Overlooked Sorrel (Rumex acetosa subsp. biformis) until Mike Wyse Jackson gave me a record for it growing on Helvick Head, Co. Waterford (H6), and Saltee Island Great, Co. Wexford (H12) in 2016. I kept promising myself that I would go and take a look, but this didn’t happen until May 2021. The New Flora of the British Isles (Stace, 2019) lists four subspecies of Rumex acetosa. They all occur in Ireland. The only one that is common is subsp. acetosa (Common Sorrel), which grows in a wide variety of grassland habitats, and on roads banks, etc. Subsp. hibernicus (Irish Sorrel) is restricted to sand dunes around the coast, mainly in the south and west, is a much smaller plant, and is covered in yellow papillose (gland-like) hairs. The fourth is subsp. ambiguus (Garden Sorrel), and is grown as a vegetable. It is a very rare escape from cultivation in Ireland. Stace (2019) lists Overlooked Sorrel as occurring in one Vice-county each in England (West Cornwall VC1), Wales (Cardiganshire VC46), and Ireland (Co. Clare H9). The BSBI handbook, Docks and Knotweeds of Britain and Ireland (Akeroyd, 2014) adds North Kerry (H2). The BSBI database (DDb) has two additional Vice-counties for the UK listed: East Cornwall (VC2), and Pembrokeshire (VC45), both with Overlooked Sorrel recorded from one hectad each. The DDb doesn’t have any records for North Kerry and Co. Clare, but does include the Counties Waterford and Wexford records mentioned above, a record for South Kerry (H1), and my records made in 2021 for Counties Waterford and Wexford.

The earliest Irish record

The DDb would suggest a 2002 record by Mike Wyse Jackson from coastal grassland on Helvick Head (X3088), Co. Waterford is the first Irish record. In a strange twist Helvick Head is correct, as a specimen held in the herbarium at the National Botanic Gardens, Dublin (DBN), has a specimen collected by Donal Synnott in 1964 which is in my opinion R. acetosa subsp. biformis. Did Synnott collect this specimen because he realised the plants were different?

Distribution in Ireland

It is likely that Overlooked Sorrel is extremely under recorded around the Irish coast (Figure 1). I expect it will be found to be frequent, especially where the sea-cliffs are rock, as it mostly occurs where the soil is shallow and there isn’t too much competition from other species.

South Kerry (H1)

Tearaght Island (V19), 1975, G.A. Walton, DBN, confirmed J.R. Akeroyd. Fahamore, Magharee Peninsula (Q600190), 2017, A. O’Connor, M. Wyse Jackson, S. Wyse Jackson.

North Kerry (H2)

Kerry Head (Q63), Docks and Knotweeds of Britain and Ireland (Akeroyd, 2014).

Waterford (H6)

Helvick Head – see above – seen here in 2021 by me. Ardmore Head (X27), 1964, D. Synnott, DBN, det. P.R. Green. I found it to be abundant amongst the cliff-top vegetation in 2021. Plentiful on top of sea-cliffs, Ram Head (X199767), 2021, P.R. Green. Little on cliff edge, Paulsworth (X212803), 2021, P.R. Green. At top of beach, and on low sea-cliffs, Ballymacart Cove, (X252810), 2021, P.R. Green.

Clare (H9)

Sea-cliffs, south of car park, Cliffs of Moher (R09), 1971, M.J.P. Scannell, DBN, confirmed J.R. Akeroyd.

Wexford (H12)

Saltee Island Great (X947966), 2016, A. O’Connor, M. Wyse Jackson, S. Wyse Jackson. I found it to be very abundant on the island in 2021, and in places it formed large red carpets, and was the dominant plant (see page 41). One large clump on dune, Carnsore Point (T115039), 2021, P.R. Green. A few on steep slope above sea-cliff, Broomhill (S745048), 2021, P.R. Green. Coastal grassland on top of sea-cliff, Baginbun Head (S798031), 2021, P.R. Green. Five in herb-rich pasture, Churchtown (X739984), 2021, P.R. Green. This site is the only one where it is not directly next to the sea, as it is 0.5km inland. It is the only field left on the Hook Peninsula which has good semi-natural grassland. Species include: Bromus racemosus (Smooth Brome), Dactylorhiza fuchsii (Common Spotted-orchid), D. kerryensis (Irish Marsh-orchid) and Linum bienne (Pale Flax).

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Figure 1. Vice-county map showing known hectads for Overlooked Sorrel