Salix pentandra
Bay willow

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Bay-leaved willow (Salix pentandra) is a medium-sized deciduous willow native to northern and central Europe and parts of northern Asia. At the northern limit of its range, the species occurs only in lowlands and is restricted to the forest belt (Skvortsov, 2014). At its southern distribution limit, it is nearly entirely confined to wetlands and mountainous areas (Skvortsov, 2014). Bay-leaved willow thrives in nutrient-rich, moist soils and plays an ecological role in stabilizing wetland margins and providing resources for insects. It's typical natural environments are sedge/bluejoint (Calamagrostis canadensis) forested wetlands and transitional zones around sphagnum bogs (Skvortsov, 2014). It is recognized for its glossy, aromatic leaves and upright growth form, and is valued ornamentally for its glossy foliage, used locally for basketry, and sometimes planted for erosion control along water margins. 

in situ genetic conservation unit+
ex situ genetic conservation unit+
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Acknowledgements

This distribution map has been developed by the European Commission Joint Research Centre (partly based on the EUFORGEN map) and released under Creative Commons Attribution 4.0 International (CC-BY 4.0)


Caudullo, Giovanni; Welk, Erik; San-Miguel-Ayanz, Jesús (2017). Chorological maps and data for the main European woody species. figshare. Collection. https://doi.org/10.6084/m9.figshare.c.2918528

 

The following experts have contributed to the development of the EUFORGEN distribution maps:

Fazia Krouchi (Algeria), Hasmik Ghalachyan (Armenia), Thomas Geburek (Austria), Berthold Heinze (Austria), Rudi Litschauer (Austria), Rudolf Litschauer (Austria), Michael Mengl (Austria), Ferdinand Müller (Austria), Franz Starlinger (Austria), Valida Ali-zade (Azerbaijan), Vahid Djalal Hajiyev (Azerbaijan), Karen Cox (Belgium), Bart De Cuyper (Belgium), Olivier Desteucq (Belgium), Patrick Mertens (Belgium), Jos Van Slycken (Belgium), An Vanden Broeck (Belgium), Kristine Vander Mijnsbrugge (Belgium), Dalibor Ballian (Bosnia and Herzegovina), Alexander H. Alexandrov (Bulgaria), Alexander Delkov (Bulgaria), Ivanova Denitsa Pandeva (Bulgaria), Peter Zhelev Stoyanov (Bulgaria), Joso Gracan (Croatia), Marilena Idzojtic (Croatia), Mladen Ivankovic (Croatia), Željka Ivanović (Croatia), Davorin Kajba (Croatia), Hrvoje Marjanovic (Croatia), Sanja Peric (Croatia), Andreas Christou (Cyprus), Xenophon Hadjikyriacou (Cyprus), Václav Buriánek (Czech Republic), Jan Chládek (Czech Republic), Josef Frýdl (Czech Republic), Petr Novotný (Czech Republic), Martin Slovacek (Czech Republic), Zdenek Špišek (Czech Republic), Karel Vancura (Czech Republic), Ulrik Bräuner (Denmark), Bjerne Ditlevsen (Denmark), Jon Kehlet Hansen (Denmark), Jan Svejgaard Jensen (Denmark), Kalev Jðgiste (Estonia), Tiit Maaten (Estonia), Raul Pihu (Estonia), Ülo Tamm (Estonia), Arvo Tullus (Estonia), Aivo Vares (Estonia), Teijo Nikkanen (Finland), Sanna Paanukoski (Finland), Mari Rusanen (Finland), Pekka Vakkari (Finland), Leena Yrjänä (Finland), Daniel Cambon (France), Eric Collin (France), Alexis Ducousso (France), Bruno Fady (France), François Lefèvre (France), Brigitte Musch (France), Sylvie Oddou-Muratorio (France), Luc E. Pâques (France), Julien Saudubray (France), Marc Villar (France), Vlatko Andonovski (FYR Macedonia), Dragi Pop-Stojanov (FYR Macedonia), Merab Machavariani (Georgia), Irina Tvauri (Georgia), Alexander Urushadze (Georgia), Bernd Degen (Germany), Jochen Kleinschmit (Germany), Armin König (Germany), Armin König (Germany), Volker Schneck (Germany), Richard Stephan (Germany), H. H. Kausch-Blecken Von Schmeling (Germany), Georg von Wühlisch (Germany), Iris Wagner (Germany), Heino Wolf (Germany), Paraskevi Alizoti (Greece), Filippos Aravanopoulos (Greece), Andreas Drouzas (Greece), Despina Paitaridou (Greece), Aristotelis C. Papageorgiou (Greece), Kostas Thanos (Greece), Sándor Bordács (Hungary), Csaba Mátyás (Hungary), László Nagy (Hungary), Thröstur Eysteinsson (Iceland), Adalsteinn Sigurgeirsson (Iceland), Halldór Sverrisson (Iceland), John Fennessy (Ireland), Ellen O'Connor (Ireland), Fulvio Ducci (Italy), Silvia Fineschi (Italy), Bartolomeo Schirone (Italy), Marco Cosimo Simeone (Italy), Giovanni Giuseppe Vendramin (Italy), Lorenzo Vietto (Italy), Janis Birgelis (Latvia), Virgilijus Baliuckas (Lithuania), Kestutis Cesnavicius (Lithuania), Darius Danusevicius (Lithuania), Valmantas Kundrotas (Lithuania), Alfas Pliûra (Lithuania), Darius Raudonius (Lithuania), Robert du Fays (Luxembourg), Myriam Heuertz (Luxembourg), Claude Parini (Luxembourg), Fred Trossen (Luxembourg), Frank Wolter (Luxembourg), Joseph Buhagiar (Malta), Eman Calleja (Malta), Ion Palancean (Moldova), Dragos Postolache (Moldova), Gheorghe Postolache (Moldova), Hassan Sbay (Morocco), Tor Myking (Norway), Tore Skrøppa (Norway), Anna Gugala (Poland), Jan Kowalczyk (Poland), Czeslaw Koziol (Poland), Jan Matras (Poland), Zbigniew Sobierajski (Poland), Maria Helena Almeida (Portugal), Filipe Costa e Silva (Portugal), Luís Reis (Portugal), Maria Carolina Varela (Portugal), Ioan Blada (Romania), Alexandru-Lucian Curtu (Romania), Lucian Dinca (Romania), Georgeta Mihai (Romania), Mihai Olaru (Romania), Gheorghe Parnuta (Romania), Natalia Demidova (Russian Federation), Mikhail V. Pridnya (Russian Federation), Andrey Prokazin (Russian Federation), Srdjan Bojovic (Serbia) , Vasilije Isajev (Serbia), Saša Orlovic (Serbia), Rudolf Bruchánik (Slovakia), Roman Longauer (Slovakia), Ladislav Paule (Slovakia), Gregor Bozič (Slovenia), Robert Brus (Slovenia), Katarina Celič (Slovenia), Hojka Kraigher (Slovenia), Andrej Verlič (Slovenia), Marjana Westergren (Slovenia), Ricardo Alía (Spain), Josefa Fernández-López (Spain), Luis Gil Sanchez (Spain), Pablo Gonzalez Goicoechea (Spain), Santiago C. González-Martínez (Spain), Sonia Martin Albertos (Spain), Eduardo Notivol Paino (Spain), María Arantxa Prada (Spain), Alvaro Soto de Viana (Spain), Lennart Ackzell (Sweden), Jonas Bergquist (Sweden), Sanna Black-Samuelsson (Sweden), Jonas Cedergren (Sweden), Gösta Eriksson (Sweden), Markus Bolliger (Switzerland), Felix Gugerli (Switzerland), Rolf Holderegger (Switzerland), Peter Rotach (Switzerland), Marcus Ulber (Switzerland), Sven M.G. de Vries (The Netherlands), Khouja Mohamed Larbi (Tunisia), Murat Alan (Turkey), Gaye Kandemir (Turkey), Gursel Karagöz (Turkey), Zeki Kaya (Turkey), Hasan Özer (Turkey), Hacer Semerci (Turkey), Ferit Toplu (Turkey), Mykola M. Vedmid (Ukraine), Roman T. Volosyanchuk (Ukraine), Stuart A'Hara (United Kingdom), Joan Cottrell (United Kingdom), Colin Edwards (United Kingdom), Michael Frankis (United Kingdom), Jason Hubert (United Kingdom), Karen Russell (United Kingdom), C.J.A. Samuel (United Kingdom).
 

Genetic diversity and variation 

Research specifically addressing the genetic diversity of bay-leaved willow is very limited. However, insights from broader studies on European willows suggest that the species likely has similar genetic patterns to other willow species. Most European willows have high genetic diversity within populations and relatively low differentiation between populations due to obligate outcrossing, wind- or insect-mediated pollination, and effective long-distance seed dispersal (Wagner, He, and Hörandl, 2021). 

Gene flow 

Bay-leaved willow is dioecious, with separate male and female individuals. Pollen is dispersed primarily by wind and insects, promoting cross-pollination, while seeds are dispersed by wind and capable of travelling long distances, supporting extensive gene flow and mixing across populations. 


The bibliographic review was conducted by James Chaplin of the EUFORGEN Secretariat in August 2025.

Interspecific taxa dynamics 

There are roughly 400 species in the willow genus distributed across most continents (Skvortsov, 2014). Hybridization is common in willows, often occurring after climatic shifts or secondary contact, and can introduce new genetic material into populations, increasing genetic diversity and adaptive potential (Wagner, He, and Hörandl, 2021). Homoploid hybridization is frequent, while polyploidy is an important speciation mechanism in the genus, with about 40% of European willow species being polyploid (Wagner, He, and Hörandl, 2021). Although bay-leaved willow is typically diploid, it can hybridize with other willow species where their ranges overlap, contributing to local genetic variation and potentially influencing genetic distribution patterns (Wagner, He, and Hörandl, 2021). 
 

The bibliographic review was conducted by James Chaplin of the EUFORGEN Secretariat in August 2025.

Threats 

Almost no species-specific research exists for bay-leaved willow. Most available information comes from broader studies on the willow genus. Potential threats include habitat loss in wetlands and bog edges, drainage of riparian systems, and climate-driven shifts that may alter population connectivity. As in other willows, increased hybridization under changing environmental conditions could dilute locally adapted gene pools, but this remains unconfirmed for bay-leaved willow. The lack of targeted studies makes it difficult to assess genetic risks, highlighting a significant research gap. 

Management 

Management for bay-leaved willow is inferred from other willow species. Conserving wetland habitats, maintaining hydrology, and protecting mixed willow communities can help preserve genetic diversity. However, because almost no genetic studies exist for bay-leaved willow, species-specific management strategies cannot yet be defined, and further research is needed. 
 

The bibliographic review was conducted by James Chaplin of the EUFORGEN Secretariat in August 2025.

Further reading

NA

References

Skvortsov, A.K. 2014. Bay-leaved willow (Salix pentandra L.) and related species: Taxonomic and geographic overview. Skvortsovia: International Journal of Salicology and Plant Biology, 1(2):187–206. 

Wagner, N.D., He, L., and Hörandl, E. 2021. The evolutionary history, diversity, and ecology of willows (Salix L.) in the European Alps. Diversity, 13(4): 146. https://doi.org/10.3390/d13040146 

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