Species fact sheet

Yellow Centaury Cicendia filiformis Yellow centaury is a member of the gentian family (Gentianaceae). It is a tiny slender plant 2-12 cm in height with a few fleshy pinkish-green stems and linear leaves 2-6 mm long. The terminal flowers only open in the sun, revealing the four yellow petals (often tinged pink).

© Hans Hillewaert under Creative Commons BY-SA licence

Lifecycle Yellow centaury is a short-lived spring germinating annual flowering in August and September. Seeds require sparsely vegetated or bare ground to germinate and plants are often present around the edge of temporary autumn/winter pools, and can be found in the draw-down zone around the edges during the summer. Habitat It is found around seasonally-flooded pools, along rutted trackways and on scrapes on wet grass heath with sandy or peaty soils. More rarely, it is also present in tightly grazed seasonally-damp acid grassland and serpentine erosion pans, woodland rides, dune slacks and on coastal cliffs. The key element is the open nature of habitat with reduced competition allowing this tiny annual to complete its life cycle. Distribution In England, in recent years this native species has been restricted to heathland areas in Cornwall, Devon, Dorset, the New Forest and the Sussex Weald. It is now extremely rare in both Devon and Sussex and rapidly declining in Cornwall and Dorset. The key areas for this Yellow centaury distribution across plant are the Lizard Peninsula and New Forest where it Britain and Ireland is still widespread. It is also present in Wales on the The data used to create these maps has St David’s Peninsula’s grass heath commons and in been provided under licence from the south west Ireland. Some new populations of yellow Botanical Society of Britain and Ireland centaury have recently been discovered in south- (BSBI) and accessed from the Society’s online distribution database. west England and Ireland off-setting some localised population losses. Yellow Centaury Species Cicendia filiformis fact sheet Habitat management for yellow centaury GB Status and rarity Yellow centaury is reliant on reduced competition with other plants, Yellow centaury is classified as which is created by winter flooding, grazing and disturbance. Lack ‘Nationally Scarce’ (recorded in 16-100 of management, in particular under-grazing resulting in ranker hectads in Great Britain) and classified vegetation and scrub encroachment, will threaten the survival of this as ‘Vulnerable’ in The Vascular Plant Red plant. Conservation should focus on reinstating extensive grazing to Data List for Great Britain 2005 because wet heathland sites where the species occurs or formerly occurred, of a significant decline in its area of occupancy. It is considered to be a good combined with restoration and re-use of infrastructure features such as indicator species of habitat quality of seasonally-flooded pools and trackways. lowland acid grassland and heathland mosaics and tends to occur with a variety Conservation work to remove scrub along two adjacent trackways of other scarce and declining plants on the Lizard Peninsula in Cornwall resulted in the re-appearance of including three-lobed water-crowfoot yellow centaury from buried seed. In 2011, these restored populations Ranunculus tripartitus, chaffweed numbered over 4000 plants. Vehicle movements creating ruts on Dowrog Anagallis minima, allseed Radiola Common in Pembrokeshire have also increased the habitat for this plant linoides and pillwort Pilularia globulifera. where access tracks have been used to facilitate management of the commons. Bare soil is maintained through cattle and pony grazing. Reasons for decline Historically many sites were lost due to heathland reclamation and drainage, Work should be targeted around or adjacent to surviving populations though more recently cessation of grazing, or at historical sites where yellow centaury is no longer present as the infilling of ephemeral water bodies and seed does have some longevity and may germinate once it is exposed upgrading of muddy trackways with following conservation works. hardcore have posed greater threats. For example, during the 1980s at least two key trackway systems on the Lizard were in-filled with hardcore to improve public Vehicle movements can create ruts which also help increase the habitat for this plant. access removing the temporary pools utilised by yellow centaury. Protection under the law This plant is included as a species “of principal importance for the purpose of conserving biodiversity” under Section 41 (England) of the Natural Environment and Rural Communities Act 2006. Survey method Individual plants are easily identifiable around temporary pools and a census should be undertaken. Where a large number of plants are present around a particular pool the population can be estimated. Like other annuals of this type, populations can fluctuate greatly from year to year with thousands of plants one season and none in some years with less favourable conditions. A single season’s data is therefore unlikely to be sufficient to

© Lauren Tucker judge the health of a population.

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