Somerton and the Oxford Canal

Botanists botanising by the Oxford Canal. Remark the use of modern technology. Image by Fay Banks

Recording for Atlas 2020 in Oxfordshire continues. The target of this Sunday's meeting was the county's most under-recorded 10km square, SP42. Earlier in the spring I wrote about a recording outing of mine in SP42 at Tackley, and this week the venue was the parish of Somerton in SP42Z, further north along the River Cherwell/Oxford Canal. There will be another meeting in SP42Z on 8th July at Bestmoor SSSI, when we will survey the huge population of the nationally scarce Oenanthe silaifolia (narrow-leaved water-dropwort).

Sporangia of P. interjectum x100, with few thick-walled (indurated) cells forming the annulus and two basal cells between this and the stalk

The five of us who met at Somerton were blessed with wonderful weather and some fabulous plants. We started at the churchyard of St James’ which was a tidy disappointment, however. An exhibitor at the church exhorted us to come in afterwards for coffee and artwork, but we conveniently forgot and instead went to the Bell Inn in Lower Heyford! The only interesting native species in the village was a large amount of the fern Polypodium interjectum (intermediate polypody) on a shaded wall. Contrary to previous records I am finding that this is a common fern of limestone walls in Oxfordshire. I’d be grateful if other recorders would check any Polypodium they find microscopically, or record it as P. vulgare sens. lat. rather than attempt an identification based on frond morphology as this is not reliable.

We left Somerton southwards across bright green agricultural grassland and wheat fields infested with Alopecurus myosuroides (black grass). At this point I began to worry about our species list. A short detour out of SP42Z into SP42Y gave us Senecio viscosus (sticky groundsel) by the railway, from where we looped back into our tetrad and picked up the Oxford Canal. From here our fortune turned.