Thursday, 12 May 2011

PLANT: Fen Violet in central England

May 9, 2011:
Fen Violet (Viola persicifolia Schreb.) is a very scarce plant and in Britain is now only reliably found at a single locality in central England. A visit there this week revealed several hundred plants in full flower.

Much of the success of the plant here is due to conservation work carried out over recent years by a band of dedicated botanists. The locality is a fen meadow which approaches the NVC classification M24 (Molinia caerulea-Cirsium dissectum) and where other interesting plants grow nearby.

[Fen Violet, all above]

[The habitat where Fen Violet occurs; local botanists assessing the population]

Also found here is the related Dog Violet (Viola canina) with which the Fen Violet sometimes hybridises (V. x ritschliana). Dog Violet and the (sterile) hybrid appeared to be scarce here this year although a few plants were found.

[Flower of the hybrid, V. x ritschliana]

Fen Violet is characterised by its broad, very pale blue-white flowers, its greenish coloured spur and narrowly ovate, subcordate leaves. The hybrid approaches Dog Violet in flower characters and Fen Violet in habit. Fen Violet also occurs spasmodically in small numbers at two localities in eastern England and was much more widespread in past centuries before drainage reclamation drastically reduced its habitat.

Good populations are also known in the Burren area of western Ireland where it grows as the lowest zonal layer of violets on the sides of turloughs (small lakes with rapidly changing water levels). There the hybrid grows slightly above the Fen Violet with V. canina forming the uppermost zone. I saw it here in 1989 when all three taxa were locally profuse.

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