Matthiola sinuata

Matthiola sinuata (L.) R.Br. (Brassicaceae)

Sea stock, Murwyll Tewbannog Arfor

Status in Britain: VULNERABLE.

Status in Europe: Not threatened.

M. sinuata is a conspicuous plant of sand-dunes and sea-cliffs. Most colonies are on young, fairly mobile dunes, often near the drift-line or around low-lying, relatively damp blow-outs, where its local populations fluctuate rapidly in numbers and are often short-lived. Ammophila arenaria, Calystegia soldanella, Elytrigia juncea, Eryngium maritimum, Festuca rubra, Lotus corniculatus, Ononis repens and Senecio jacobaea are its typical associates. Cliff populations have apparently always been small but perhaps more stable in numbers.

It is biennial in cultivation, but in the field rosettes often take several years to reach the flowering stage and, although normally monocarpic, sometimes perennate after flowering. At the rosette stage, and also in plants that are starting to flower, adventitious rosettes are produced freely from the lower stem or fleshy roots if the leafy shoots are severed by grazing or wind-throw. Flowering is from June to August. The large, night-scented, pale purple flowers, borne in a spreading, branched inflorescence up to about 70 cm high, are adapted for and visited mainly by Lepidoptera, especially noctuid moths. British plants are self-compatible, with high pollen and seed fertility. After flowering, the dry inflorescence, which retains some viable seeds within undehisced siliquae for several months, may be dispersed both by wind-tumbling across dunes or cliffs and by floating on water. Long-distance dispersal with flotsam to new drift-line sites, although infrequent, seems likely to have been a major factor in its history and distribution.

M. sinuata was formerly known from several coastal areas in western Britain from the Isles of Scilly to Anglesey, but there are recent records only from Devon and Glamorgan. It was rediscovered in the latter county in 1964, after having been unrecorded since 1848. In both Devon and Glamorgan, scattered populations occur across groups of extensive dune-systems, most lying within protected sites. In south-west Glamorgan, estimates in 1994 showed that the main and outlying populations exceeded 2,000 plants (predominantly non-flowering rosettes), with 50-150 plants in each of five or six other sites along about 45 km of the coast. In North Devon, it occurs along a 7 km stretch of coast, also in local abundance. However, the history of the species in Britain and Ireland since the seventeenth century shows that all but one (the North Devon population) of the local populations that have been discovered have subsequently become extinct, in several cases after a period when it appeared to be well-established. The causative factors are uncertain, although disease, predation, and fluctuation (random or weather-driven) of population size below critical levels could all have been involved. 

It is a plant of Mediterranean and Atlantic coasts, widespread in the Mediterranean and at its northern limit in Britain and Ireland. It is still locally frequent on the western coasts of France, but perhaps decreasing. It extends beyond Europe to North Africa, Turkey and Israel.

Q. O. N. Kay