A rhizomatous, perennial herb usually found on moist, nutrient-rich, usually basic, soils in wooded gorges and on a wooded river bank. Plants reproduce vegetatively, by rhizomatous spread, but fruiting is generally poor, with recruitment from seed apparently very infrequent. Lowland.
The distribution of P. verticillatum is stable, though some populations have been lost through erosion and habitat destruction. Flowering seems to be restricted by excessive shading at a number of localities and limited opportunities for cross-pollination further restrict seed production.
European Boreal-montane element.
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Light (Ellenberg): 4
Moisture (Ellenberg): 5
Reaction (Ellenberg): 5
Nitrogen (Ellenberg): 5
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 1.2
July Mean Temperature (Celsius): 13.1
Annual Precipitation (mm): 1061
Height (cm): 80
Perennation - primary
Life Form - primary
Clonality - primary
Count of 10km squares in Great Britain: 10
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 0
Plantatt Conservation Status
RDB Species Accounts
Polygonatum verticillatum (L.) All. (Liliaceae)
Whorled Solomon's seal, Sêl Selyf Culddail
Status in Britain: VULNERABLE. WCA Schedule 8.
Status in Europe: Not threatened.
All sites for P. verticillatum are in thickly wooded gorges associated with ancient woodland, the one exception being a narrow strip of woodland along a level river bank. In some places it occurs on wet unstable slopes which are highly vulnerable to disturbance and trampling. High soil moisture and air humidity are the principal habitat requirements, and base-rich substrates and fertile soils are favoured. In areas of acidic geology additional nutrients are received from flushing, snow-melt, mineral downwash and periodic flooding. It rarely occurs in coniferous woodland, except where conifers have been planted on sites of former broad-leaved woods. The diversity of woodland types in which it occurs is reflected in the wide range of associates. At some, accompanying species include Deschampsia cespitosa, Dryopteris filix-mas, Holcus mollis, Luzula sylvatica, Oxalis acetosella and Phegopteris connectilis; elsewhere it may occur with Ajuga reptans, Allium ursinum, Crepis paludosa, Geum rivale, Melica nutans and Mercurialis perennis. There is often a good cover of bryophytes including Eurhynchium praelongum, E. striatum and Thuidium tamariscinum.
P. verticillatum is a clonal, summer-green rhizomatous herb. Shoots emerge in late April and May with flower buds opening in late May to early June. Flowering is recorded in half the Scottish populations, but the proportion of flowering shoots ranges from less than 0.5% to 50%. The incidence of flowering is related to light and soil conditions. In nutrient-poor sites, shoots are small and mostly sterile, in nutrient-rich sites they are large. The plant flowers well only in open or semi-shaded places. It is partially self-compatible, but spontaneous selfing is rare. Bumblebees appear to be the most important pollinators. Fruiting is very poor but variable, a shortage of cross-pollen being one reason, and the number of seeds within fruits is well below the observed number of ovules. Seedlings have been detected in wild populations, but recruitment from seed appears to be very infrequent in established populations (Wright, et al. 1993).
This species was discovered in the wild in 1790 by George Don, but was grown as a medicinal herb in Britain possibly as early as the fifteenth century. A total of sixteen discrete populations are currently known, but from only nine sites, all in the Tay catchment in Perthshire, though it formerly occurred in Northumberland and at least three other sites in Perthshire. Losses have been due to habitat destruction, erosion and collecting. The sixteen known populations held between two and about 2,000 shoots in 1995. However, since several populations may comprise a single or few clones, the genetic stock might be very limited.
All but two sites have statutory protection, though all colonies are threatened. Erosion of stream banks, and soil slippage are the most immediate threats at two sites, one of which has been progressively undercut in recent years such that rhizomes are now exposed. One population seems to be suffering reduced vegetative vigour owing to reduced fertility under spruce, and at least three populations are at risk because of their small size. roe deer cause some damage by trampling and soil displacement, but appear rarely to graze the shoots. All populations now lie close to the woodland edge where they are more vulnerable to various disturbances and disruptive processes, including windthrow, soil erosion, agricultural run-off, reduction in air humidity, summer drought, human disturbance, and competition from more light-demanding plants. Flowering is particularly sensitive to summer drought, and warmer winters may be detrimental to species with endogenous winter dormancy. The present isolation of populations may be restricting the chances of cross-pollination.
P. verticillatum has a sub-oceanic distribution extending from 70°N in Norway through western Scandinavia, Denmark and central Europe to the Pyrenees, Apennines, Carpathians and Caucasus. From Russia it extends eastwards to the Himalayas. It ranges from sea level in Arctic Norway to the alpine zone, but is predominantly sub-montane. In Europe, it is mostly confined to deciduous forest, but also occurs in sub-alpine birch-willow scrub, species-rich tall-herb vegetation, and wooded meadows (Carlsson 1991).