Trinia glauca ( honewort) is a low-growing umbellifer found in rocky areas.
Description
Honewort is a low-growing glabrous plant. Its stems can reach 20 cm, and are surrounded by abundant fibrous remains of petioles at the base. It is much-branched, with the branches spreading at a wide angle. The leaves are glaucous, and are 2- to 3- times pinnate, although upper leaves are less divided. The inflorescence is an umbel, with white flowers, and no sepals. It has an ovoid, laterally compressed fruit.
[Tutin, T. G. (1980) Umbellifers of the British Isles (BSBI Handbook no. 2) , pages 124-5]
Taxonomy and nomenclature
The genus
Trinia is named after the German-born botanist Carl Bernhard von Trinius.
Habitat
In Britain, honewort is restricted to dry stony limestone sites, typically occurring in short, open, grazed turf on south-facing slopes.
Status and distribution
Honewort is found in central and southern Europe, north to southern England, and in southwest Asia.
Status in Britain
In Britain, honewort is found as a native species in three areas, all in southwest England: the
Avon Gorge near Bristol, coastal limestone in South Devon, and in the western
Mendip Hills (including the adjacent coast). Its British range covers around 20 sites in all, and the two largest native populations, comprising around 10,000 plants each, are both in this last area, at Sand Point and
Crook Peak.
[Wigginton, M. J. (1999) British Red Data Books 1. Vascular Plants , page 378] British populations are all of
subspecies glauca.
[Sell, Peter and Gina Murrell (2009) Flora of Great Britain and Ireland, volume 3 Mimosaceae - Lentibulariaceae , page 289]
In the Avon Gorge, it was first found by William Turner in 1562, one of the first rare plants to be documented in Britain.[Myles, Sarah (2000) The Flora of the Bristol Region , pages 25-34 and 161][Marren, Peter (1999) Britain's Rare Flowers , pages 16-7, 39-43 and 303-4] The stronghold of the species is in the western Mendip Hills, where it was first found by Dillenius in .[Roe, R. G. B. (1981) The Flora of Somerset , page 131] Here, in addition to the Crook Peak and Sand Point sites, it is found on Purn Hill,[ SSSI citation sheet for Purn Hill, Natural England (retrieved 7 June 2009)] on Wavering Down, Cross Plain and Axbridge Hill,[Green, Paul R., Green, Ian P. and Geraldine Crouch (1997) The Atlas Flora of Somerset , page 137] at Hellenge Hill and South Hill near Bleadon,[Ivimey-Cook, R. B. (1984) Atlas of the Devon Flora , page 121]
It also occurs at Goblin Combe in North Somerset, where it was introduced as an experiment.
Conservation
In Britain, several of the species' sites are protected as Sites of Special Scientific Interest.
