Pulsatilla vulgaris (L.) Mill. Pasque Flower, Pulsatilla vulgaris Miller RANUNCULACEAE SYN.: Anemone pulsatilla L. Status: All British populations belong to subsp. vulgaris which is classified as ‘vulnerable’ (IUCN Criterion A2ac; Cheffings & Farrell, 2005), and listed as a UK BAP Priority Species in 2007. It is currently confined to 18 sites in 19 10km squares in England. In this account Pulsatilla vulgaris refers to subsp. vulgaris unless otherwise stated. In partnership with: 1 Contents 1 Morphology, identification, taxonomy and genetics 1.1 Morphology and identification 1.2 Taxonomic considerations 1.3 Genetic implications 1.4 Medicinal properties 2 Distribution and current status 2.1 World 2.2 Europe 2.3 United Kingdom 2.3.1 England 2.3.1.1 Native populations 2.3.1.2 Introductions 2.3.2 Northern Ireland, Scotland & Wales 3 Ecology and life cycle 3.1 Life cycle and phenology 3.1.1 Flowering phenology 3.1.2 Flower biology 3.1.3 Pollination 3.1.4 Seed production 3.1.5 Seed viability and germination 3.1.6 Seed dispersal 3.1.7 Regeneration 3.1.8 Response to competition 3.1.9 Herbivory, parasites and disease 4 Habitat requirements 4.1 The landscape perspective 4.2 Communities & vegetation 4.3 Summary of habitat requirements 5 Management implications 6 Threats/factors leading to loss or decline or limiting recovery 7 Current conservation measures 7.1 In situ Measures 7.2 Ex situ Measures 7.3 Research Data 7.4 Monitoring and the Common Monitoring Standard 8 References 9 Contacts 10 Links 11 Annex 1 – site descriptions 13 Annex 2 – changes in population size, 1960-2006 14 Annex 3 – associates 2 1 Morphology, identification, taxonomy and genetics 1.1 Morphology and identification Hemicryptophyte; 2-15 cm, extending to ca. 45 cm in fruit. Rhizome obliquely erect or vertical, branching, black, 2-17 mm thick, eventually decaying to form new plants. New leaf rosettes arising from the branches of the rhizome by growth of lateral buds, producing groups of leaf rosettes connected below ground by an anastomosing rhizome system. The remains of old leaf bases protect the overwintering buds at the apex of the rhizome. Basal leaves up to 11 from each rhizome apex, bipinnatisect, silky-hairy and forming a rosette. Ascending, developing during anthesis and withering in the autumn (occasionally over-wintering). Petiole to 21 cm, blade to 11 × 7 cm, 2- to 4- pinnate. Cauline leaves 2(-4), sessile, 1.7-5.3 cm, smaller and more deeply divided into linear segments (only slightly lobed), white-hairy and reaching the perianth during most of the flowering period. All leaves silky-hairy at least initially, the basal with pubescent petioles. On emergence the silky-villose leaves are tightly curled around the apical growing points. Flowers solitary, terminal, erect at first but drooping after a few days, and becoming bell-shaped (campanulate) (Fig. 1a). Buds develop during late summer and become dormant over the winter months when they are protected by a dense covering of silky-villose hairs and the remains of the previous year’s leaves. Pedicel up to 8 cm and bent over less than 90º at anthesis, elongating to 25 cm in fruit. Perianth-segments 6, 16- 42 × 4-17 mm, deep violet-purple in British plants, more blue to violet-blue on the Continent, darker on the inside, paler and silky on the outside (rarely white or pink), subequal, only slightly curving outwards apically. Petals fading and becoming bleached after about a week. Stamens numerous, 50-120 per flower, crowded, the outermost shorter, sterile, club-shaped and secreting nectar. Staminodes and fertile stamens not more than half as long as perianth segments, 15-25 mm; filaments stout at the base, tapering to the adnately attached anthers, which are bright golden-yellow before fading. Styles purple, borne on a flattened, conical, receptacle, 30-90 per flower, each with a single functional ovule. Fruit is an achene, 2-3 mm long, with a single embryo, covered with simple, silky hairs and with a persistent feathery style 3.5-5 cm long. The internode between the stem leaves and flower elongates considerably after flowering, increasing the height at which the achenes are released (Fig. 1b). Flowers 1- 3(-12) per plant, actinomorphic, hermaphrodite and protogynous in England, pollinated by a variety of insects, especially bees (Apidae: Apis, Bombus). 1.2 Taxonomic considerations The common name Pasque Flower has several derivations; one is reputedly from the Latin pascha, meaning Easter, as Easter eggs were often stained by rubbing the eggs with the flowers and leaves for celebration. Originally the flower was known by the French as the ‘passe-fleur’, and then changed by Gerard (who considered it to be a worthy addition to the herbaceous border) to the ‘Pasque Flower’ on account of the flowers appearing around Easter time (Smith, 1996). 3 Figure 1 – Pulsatilla vulgaris: (a) flowers, Knocking Hoe, Bedfordshire, photo by K.J Walker; (b) elongated scape and achenes, Devil’s Dyke, Cambridgeshire, photo by K.J. Walker; (c) illustration by Stella Ross-Craig (1948). Pulsatilla vulgaris was described by Carl Linnaeus (1753) as Anemone pulsatilla in the first volume of his Species plantarum (p. 539)1. The Scottish botanist Philip Miller (1768) changed the name to Pulsatilla vulgaris in the eight edition of The gardeners dictionary and this was subsequently retained in Aichele & Schwegler’s (1957) monograph of the genus which described a number of taxa within the Pulsatilla vulgaris group. As no holotype exists a lectotype has recently been designated from Linnaeus’ herbarium (Herb Linn. No. 710.5; Jarvis et al., 2005). This herbarium sheet contains a single flowering and two fruiting stems but has no collection details and thus its origin is unknown.2 Pulsatilla is a small genus within the large, primitive family Ranunculacae. The division of the Linnaean concept of ‘Anemone’ into three genera, Anemone sensu stricto, Hepatica and 1 see http://www.biodiversitylibrary.org/page/358106#551 2 see http://www.linnean‐online.org/5012/ 4 Pulsatilla is now generally accepted based on both morphology and chloroplast DNA (e.g. Hantula et al., 1989). Morphologically Pulsatilla taxa are distinguished by the styles elongating greatly and becoming feathery in fruit and the presence of nectar-secreting staminodes (both absent in Anemone sensu stricto; Akeroyd, 1993). The current worldwide classification scheme of the Angiosperm Phylogeny Group (APG III) considers the Ranunculaceae to be among the most basal of the derived Eudicots clade (Hill & Preston, 2002): APG Clade: EUDICOTS APG Order: Ranunculales APG Family: Ranunculaceae Subfamily: Ranunculoideae Genus: Pulsatilla Species: Pulsatilla vulgaris Mill. The genus Pulsatilla contains around 38 species worldwide all of which occur in the Northern Hemisphere, mainly in Europe and Asia with two species in North America. Nine species occur in Europe (Akeroyd, 1993). Five of these are restricted to the montane regions of southwest, central-south and southeast Europe (P. alba, P. alpina, P. halleri, P. montana, P. rubra); the remaining four taxa are more widespread in the lowlands of northern, central and eastern Europe extending from the Atlantic to Eurasia (P. patens, P. pratensis, P. vernalis, P. vulgaris). Pulsatilla vulgaris is told from all other Pulsatilla species by its sessile cauline leaves, deeply pinnatisect basal leaves with 7-9 primary segments that wither in the autumn and erect flowers (nodding in anthesis). It is a very variable species for which a number of poorly defined infraspecific taxa have been described in the past. These, however, appear to represent the more distinct of the numerous isolated populations and probably represent a ‘dissected continuous’ type of variation caused by post-glacial climatic changes and the intolerance of the species to ploughing, shade and bad drainage (Akeroyd, 1993). Consequently infraspecific taxa do not often appear to fall into the geographical pattern characteristic of subspecies. The smaller and more isolated populations, particularly towards the edge of the range of the species, are fairly homogeneous (as in Britain), but in other areas there is considerable variation within populations. While it is likely that most populations are separable from one another, there is a large amount of overlap between them and intermediates occur frequently. Today three subspecies are usually accepted. Subspecies vulgaris, to which all English populations belong, is the most widespread taxon extending from 61º N in Sweden to c. 45º N in the Bordeau region of France and from Gloucestershire in England to near to Poznan in western Poland where it is replaced by subsp. grandis (Lindell, 1998). Subsp. vulgaris is distinguished by the greater degree of lobing in the leaves (>100; <40 in subsp. grandis), narrower perianth segments and presence of leaves at flowering (occurring after the flowers in subsp. grandis; Akeroyd, 1993). A third taxon, subsp. gotlandica, confined to limestone pavement on the Swedish island of Gotland (Jonsell, 2001), is dubiously distinct and placed within subsp. grandis by some authorities (e.g. Akeroyd, 1993). On the whole British populations exhibit little variation although plants on the Oolitic limestone are generally larger and produce more flowers (Wells & Barling, 1971). Under heavy grazing plants also tend to be much smaller and more compact (Bailey, 1996). 5 1.3 Genetic implications The chromosome base-number of the genus is 8. Pulsatilla vulgaris is tetraploid (2n = 32) and may have arisen following hybridization