Biological Flora of Britain and Ireland:Hammarbya paludosa

Abstract

AbstractThis account presents information on all aspects of the biology ofHammarbya paludosa(L.) Kuntze (bog orchid, bog adder's‐mouth orchid) (Malaxis paludosa(L.) Sw.,Ophrys paludosaL.), that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of theBiological Flora of Britain and Ireland: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history and conservation.Hammarbya paludosais a small bisexual perennial forb. It occurs in open habitats in bogs, mires and heaths as well as semi‐shaded open woodland and, in some areas, in shaded coniferous forest. It is found in a few locations in the southern England (the New Forest, Dorset, Devon and Cornwall), in Cumbria and Northumberland, and in western counties in Wales. It is rare in Ireland but wide spread but very local in Scotland.H. paludosahas a Holarctic circumboreal range. Ninety per cent of known locations are recorded in Northern Europe and the British Isles.Hammarbya paludosaoccurs inSphagnum, other mosses and bare peat, overlying a variety of superficial deposits and sedimentary, metamorphic and igneous rocks. The pH of the rooting substrates ranges from acidic to neutral and slightly alkaline. Its nutrient status is oligotrophic, although occasionally mesotrophic, and very rarely eutrophic. It grows well in conditions of consistent lateral flow of water in the substratum.Hammarbya paludosais visited by small insects of the order Diptera. Two species of gnats are recorded as orchid pollinators: Phronia digitataandSciara thomae. It produces a small amount of nectar but is often considered as non‐rewarding. The seeds are dust‐like, dispersed by wind and water and the species has a short‐term seed bank. Tiny bulbils (propagules) are formed on the leaf margins. They are dispersed by water.Hammarbya paludosahas declined in Britain since the late 19th century primarily due to drainage of its mire habitats in lowland regions of southern and eastern England and Wales. The decline slowed down by the 2000s, and new locations have been found in Scotland and Ireland.