Biological Flora of the British Isles: Neottia cordata

Abstract

Abstract This account presents information on all aspects of the biology of Neottia cordata (L.) Rich. (Lesser Twayblade; Listera cordata (L.) R. Br.) that are relevant to an understanding of 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, reproductive characteristics, herbivores, history and conservation. Neottia cordata is an inconspicuous orchid, confined to humid heathlands and woodlands rich in bryophytes in the British Isles. Neottia cordata is a polycarpic, perennial herb with populations maintained predominantly by vegetative reproduction from root suckers. The main perennating organ is a short rhizome that produces two new internodes each year. The long adventitious roots are mainly colonized not only by mycorrhizal basidiomycetes from the Sebacinales (clade B, Serendipitaceae) but also by several other fungal groups. The species flowers from mid‐April to August depending on latitude and altitude. The flowers possess a sensitive rostellum that releases a viscid fluid when touched, ensuring that the pollinia are glued to the pollinator. The flowers produce nectar and are pollinated mainly by fungus gnats (Mycetophilidae and Sciaridae). Between 60% and 80% of open flowers set fruits. Neottia cordata is classified as Least Concern in Great Britain. It is still locally abundant in north and west Scotland but has declined elsewhere, especially at lower altitudes, because of burning on grouse moors, drainage of swamps and cutting of wet forests. It is likely to have been under‐recorded throughout its range, particularly in earlier surveys, due to its inconspicuousness.