Crepis foetida

Crepis foetida L. (Asteraceae)

Stinking hawk's-beard, Gwalchlys Drewllyd

Status in Britain: ENDANGERED.

Status in Europe: Not threatened.

During this century, C. foetida has been recorded at only a few coastal sites in south-east England, typically on disturbed shingle or chalk. Most records have been from Dungeness, none involving more than a very local scattering of plants. Though it became extinct in 1980, it was re-introduced to Dungeness in 1992 by using seed from Dungeness plants which had been cultivated at Cambridge University Botanic Garden (Ferry 1995). Plants were first established in experimental plots in the area of its last recorded occurrence at Dungeness, and by 1995 it had 'escaped' onto the adjacent shingle. The shingle ridge community comprises patches of Cytisus scoparius in a mosaic with 'shingle heath' containing Anthoxanthum odoratum, Festuca tenuifolia, Galium mollugo, Hypochaeris radicata, Pilosella officinarum, Silene uniflora, Teucrium scorodonia, Dicranum scoparium and Cladonia species. The C. foetida plants, which numbered 139 in 1995 and 168 in 1996, have colonised marginal areas of this natural community where the vegetation is very sparse and the substrate a mix of pebbles and consolidated peat. Interestingly, disturbance of the shingle does not seem to have been a prerequisite for such colonisation.

Over most of its range, C. foetida is a biennial or an annual (Babcock 1947). At Dungeness, it routinely performs as a stressed annual if grown from seed, naturally producing diminutive plants to 15 cm tall, which lack basal rosettes, have few, if any, branches, and only a few capitula. Plants grown in good soil ex situ form basal rosettes, and such plants, when transplanted onto the shingle, develop biennially and form taller, well-branched specimens with many capitula in their second year. This species is fairly easy to distinguish in the field from other similar Asteraceae by two morphological characters: nodding flower buds and the normally tightly closed, snowy white pappus.

The reasons for the extinction of C. foetida in England are not clear. Climatic factors may be involved, but whether the problem is one of germination, vegetative growth, flowering or seed-set remains to be answered. Viable seed is produced readily by plants in the field, and germination tests show that over 50% of newly-produced seed germinates in the laboratory, and about 30% in field experimental plots. Seed appears to remain viable for several years, so there is every likelihood that a seed-bank could persist. Dungeness has appreciably less rainfall and more sunshine than even adjacent regions of Kent, and is extremely well-drained. This near-Mediterranean set of conditions may suit the plant's needs, but it is not difficult to imagine the balance being tipped unfavourably in occasional years. Biotic factors may be significant. Rabbits seem to be partial to C. foetida, and the experimental plots need to be protected with wire cages to prevent transplanted biennial rosette plants from being taken by them. However, small annual plants, now escaped in some numbers onto the open shingle, seem to be ignored by rabbits. Whether the plant needs a disturbed substrate, as has often been assumed, is now less clear given the recent colonisation of undisturbed habitat around experimental plots at Dungeness. 

C. foetida is widespread throughout most of Europe, occurring on open and dry, rocky or sandy sites, both coastal and inland to altitudes in excess of 1,000 metres, and is more common in the southern and eastern parts of the continent (Davis 1975). It reaches its north-eastern limit in Britain and the north coasts of France, Germany and Poland. In Asia, it extends to central and southern Russia, Iran and the north-western Himalayas.

B. W. Ferry