Biological flora of the British Isles:: Melampyrum sylvaticum L.

1 This account reviews information on all aspects of the biology of Melampyrum sylvaticum that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history, and conservation. 2 Melampyrum sylvaticum is a hemiparasitic annual of upland, often birch-dominated woodlands. It is found across boreal and montane areas of Europe but within the UK it is predominantly found in the Scottish Highlands. These populations are consequently very isolated and vulnerable to a range of threats. Suitable habitat is characterized by open-canopied deciduous woodland close to water bodies, such as fast-flowing burns or lochs. Sites are typically north-facing, in cool and wet areas of Britain, on moderately acidic soils that are moist but freely draining. 3 Hemiparasitism allows M. sylvaticum to acquire nutrients from a range of hosts but very little is known about which species it is able to parasitize in the field. Melampyrum sylvaticum is associated with herb-rich patches of the understorey. 4 Melampyrum sylvaticum is insect-pollinated. Ants have been reported to be the main dispersal agents and the seed bears an elaiosome which offers them a lipid-rich reward. However, neither insect pollination nor ant dispersal has been observed directly in British populations. 5 Melampyrum sylvaticum has relatively large seeds and been described as an 'annual K-strategist'; it has been suggested that this unusual combination makes it vulnerable to environmental change. Because of its endangered status, M. sylvaticum has been classed as a UK Biodiversity Action Plan species and a recovery project is underway to protect existing populations and to introduce it to suitable habitats in the Central Highlands of Scotland.