THE BRYOPHYTES OF CORNWALL
AND THE ISLES OF SCILLY

Photo by Dr M Lueth ©.

*1: Near Ruan Minor, 1909, AW (GL) (Paton 1969a: 748). This record is older than that listed as new for vc1 by Warburg (1962: 376).

*2: Whitehay Moor, Withiel, no date [= late 19C], RVT (CMM) (Paton 1969a: 748).

D. sendtneri is distinct from D. aduncus mainly in having groups of alar cells that are relatively small and separated from the costa by a relatively large area of undifferentiated basal lamina cells, the alar cells extending 40-60% of distance to leaf middle at insertion, whereas the enlarged alar cells reach ±  to the costa in D. aduncus (Hedenäs 1998: 84, 98, 2003). Several other characters given for D. sendtneri by Smith (1978: 561, 563; 2004) do not provide reliable distinctions from those species.

It was realised in 2001-2005 that records of this species from dune-slacks along the north coast of Cornwall were based on misidentification of forms of D. aduncus with a strong costa, apparently including all records from the Towans (SW53U, SW54V, SW54W) and most of those from the Gear Sands-Penhale Sands areas (SW75S, SW75T, SW75Y; some of those still mapped here may also prove to be incorrect if voucher specimens can be located and checked). The errors arose because the standard flora (Smith 1978, 2004) gave inaccurate descriptions and figures of the alar cells of D. sendtneri and also relied on width of costa and other unreliable characters to separate this species from D. aduncus. Redetermination was based on the more reliable characters given by Hedenäs (2003).

Near Hayle Kimbro Pool (Lizard pen.) it grows submerged in and emergent from shallow water (<10 cm) of pool, in short fen vegetation of area that dries in most summers, and on damp ground at base of open cover of herbs in dried-up edge of large pool. Associated with Agrostis stolonifera, Calliergonella cuspidata, Eleocharis multicaulis (dominant), Hydrocotyle vulgaris (plentiful), Eleogiton fluitans, Ranunculus flammula.