This annual root-parasite was formerly a widespread weed of arable land in E. Britain. However, most of the remaining sites are on the North Downs, in grassland and open scrub on chalk. In Lincolnshire, it occurs on peat in an area of cleared Pteridium and on railway ballast. In Angus, a tiny colony survives in sandy coastal grassland. Lowland.
This species was first recorded in the wild in 1724. Nearly all its pre-1970 sites were lost before 1930. It was not recognised on the North Downs until 1966 (Lousley, 1976a). Hay cutting after flowering at some of its North Downs sites may have assisted its spread. Some old records may be errors for the variable R. minor.
Eurosiberian Boreo-temperate element.
Light (Ellenberg): 7
Moisture (Ellenberg): 6
Reaction (Ellenberg): 7
Nitrogen (Ellenberg): 2
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 3.1
July Mean Temperature (Celsius): 14.6
Annual Precipitation (mm): 809
Height (cm): 60
Perennation - primary
Life Form - primary
Clonality - primary
Count of 10km squares in Great Britain: 90
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 0
Atlas Change Index: -0.1
RDB Species Accounts
Rhinanthus angustifolius C.Gmelin (Scrophulariaceae)
R. serotinus (Schönheit) Oborny
Greater yellow-rattle, Cribell Felen Fawr
Status in Britain: VULNERABLE. WCA Schedule 8.
Status in Europe: Not threatened.
R. angustifolius grows in a range of lowland grassy habitats. It owes its wide ecological tolerance to its semi-parasitic habit, its main requirement being for a sufficient density of host roots through which it can obtain water and nutrients. It has been recorded widely across Britain, although robust forms of R. minor may sometimes have been mistaken for it, and the map may contain some errors. Nevertheless, there has been a widespread decline, the reasons for which are obscure, and it is now found in only three areas - in Surrey, North Lincolnshire and Angus.
The only area where this species is at all frequent is a small section of the North Downs on the Surrey - Greater London borders, especially Happy Valley and Farthing Downs, where it occurs in eighteen 1 km squares in six hectads. There it is now mainly a plant of meadows on the chalk, where it grows with such species as Centaurea scabiosa, C. nigra, Festuca pratensis, Helictotrichon pratense, Lathyrus pratensis and Onobrychis viciifolia. In Lincolnshire, it still occurs in two localities: on Crowle Moors, two small populations on a trackside and one close-by in an area of cleared bracken, and near Belton, in species-rich rank grassland between an old railway and arable land. At the latter site, associated species include Arrhenatherum elatius, Centaurea nigra, Dactylis glomerata, Heracleum sphondylium, Lathyrus pratensis, Leucanthemum vulgare, Leontodon hispidus, Phragmites australis, Poa trivialis, Sanguisorba officinalis and Trifolium medium. In Angus, a single tiny colony just survives in sandy coastal grassland near East Haven.
This species is an annual hemi-parasite. Flowers generally appear in late June and July, but may extend to September. They are pollinated by bumble-bees (Kwak 1978). Flowering times overlap with R. minor which, however, generally starts flowering earlier. Hybridisation is suspected, as indicated by the intermediate characters of some individuals, and it is possible that some colonies of pure R. angustifolius have disappeared through introgression. Seed germinates in spring, and plants may establish themselves in a more or less closed sward, unlike most annuals, which require patches of open ground. Studies of related species suggest that R. angustifolius can probably accept a wide range of host plants, though particular species are favoured in certain situations, such as legumes in low nitrogen soils. However, it can survive without a host, even to produce seed, though such plants are depauperate. The quality of the host plant also seems to affect the morphology of the R. angustifolius, and this has contributed to taxonomic confusion, with forms variously described as species, subspecies, and seasonal or altitudinal ecotypes.
The ideal management for R. angustifolius is a late hay-cut after seed has set. Seed has little longevity beyond the following spring, and therefore any break in continuity of seed production can quickly lead to the loss of populations. Aftermath grazing is acceptable, as is light grazing earlier in the season. The plant seems to be unpalatable to livestock. Given that distinctive forms have evolved in response to particular mowing regimes, it is highly desirable to retain the local management pattern to ensure seed production is in synchrony with mowing. At the Surrey sites, it has increased following scrub clearance and late hay cutting. It also seems to have extended its range, perhaps through seeds being inadvertently carried to new sites by mowing machinery. However, some new colonies are suspected of having originated from continental seed, as was the alien R. alectorolophum in Warwickshire.
Elsewhere, its distribution extends across much of central Europe, northwards to Scandinavia and southwards to Turkey and Siberia. It is declining in the west, but is perhaps stable further east, especially where it retains a strong presence as an arable weed.