Introduction to Dwarf Willows of Alaska

Introduction to Dwarf Willows of Alaska
The female catkins of a dwarf willow species in the Alaska Interior

Identifying individual dwarf willow species in Alaska presents a formidable challenge, even to seasoned botanists. The difficulty arises from several factors that blur the lines between these diminutive species. Firstly, the morphological similarities across dwarf willow species make field identification tricky. Many species exhibit subtle differences that may be easily overlooked without careful observation.

Furthermore, dwarf willows are notorious for their propensity to hybridize. This interbreeding adds another layer of complexity, as hybrid specimens combine characteristics from more than one species, often resulting in ambiguous traits that do not align neatly with the typical descriptions found in botanical literature. This includes hybridization between dwarf and non-dwarf willow species within the Salix genus, further complicating identification.

Additionally, photographic records, such as those on citizen science platforms like iNaturalist—which contribute data to global databases like GBIF—often contain misidentifications. These errors propagate due to the intrinsic identification challenges and a general scarcity of detailed, accessible information. Even popular field guides, such as Verna Pratt’s Alaskan Wildflowers, typically cover only the most commonly recognized species like Salix rotundifolia and Salix arctica, leaving a resource gap for identifying less common species.

Given these complexities, compiling comprehensive, individual guides for each dwarf willow species, complete with accurate identifying photographs, is currently beyond my capacity. However, this effort forms part of my broader summer project, aiming to clarify and document these species more reliably. This article marks the beginning of that work to disentangle the confusing taxonomy of Alaska’s dwarf willows, including revisiting and possibly correcting misidentified specimens in my existing Salix arctica guide.

As this work progresses, I hope to provide updates and insights to aid fellow enthusiasts in navigating the complex world of Alaska’s dwarf willows.

A few dwarf willow species

In this section, I focus on dwarf willow species cataloged in the Flora of North America, primarily from the most common species found in Alaska found in the Global Biodiversity Information Facility (GBIF). Each species description highlights a few distinguishing traits that aid identification and notes on known hybridization tendencies with other species. This selection is limited to those species documented within these authoritative sources, although future updates may expand to include additional species as more information becomes available.

Salix arctica (Arctic willow)



  • Distinguishing traits: Variable in size, non-clonal, with leaves ranging from narrow to broadly oval, often shiny on the upper side and sometimes hairy beneath. Leaves generally have a beard of fine hairs at the tip and fewer or no pores (hypostomatous) and are paler in color on the underside, which can help in water conservation in harsh climates.
  • Known hybridizations: Known to hybridize with S. arctophila, S. barclayi, S. fuscescens, S. glauca, S. herbacea, S. ovalifolia, S. pedicellaris, S. phlebophylla, S. polaris, S. rotundifolia, and S. stolonifera. Variants like S. arctica × S. arctophila combine features of both parents, often resulting in plants with intermediate traits.
  • Read more in my guidebook: Salix arctica – Alaska Wildflower Guide
  • Read more on FNA: Salix arctica – Flora of North America

Salix fuscescens (Alaska bog willow)

  • Distinguishing traits: Tends to be taller among dwarf willows, with decumbent or trailing stems. Leaves are typically narrow and oblong, potentially glaucous beneath, giving them a frosty appearance. Leaves may also have serrations near the base. Typically, it lives in very wet habitats.
  • Known hybridizations: Forms hybrids with S. arctica, S. ovalifolia, and S. phlebophylla, typically blending the characteristics such as leaf shape and hairiness.
  • Read more on FNA: Salix fuscescens – Flora of North America

Salix phlebophylla (Skeleton-leaf willow)

  • Distinguishing traits: Notable for forming clonal mats by rhizomes with trailing stems and leaves that often become skeletonized, leaving a distinctive network-like structure. Leaves are small, elliptic to circular, have ciliate leaf margins (fine hairs at the edges, helping distinguish from S. polaris), with a very glossy upper surface.
  • Known hybridizations: Hybridizes with S. arctica, S. fuscescens, and S. rotundifolia. Hybrids often exhibit traits like hairy ovaries and partially skeletonized leaves.
  • Read more on FNA: Salix phlebophylla – Flora of North America

Salix polaris (Polar willow)

  • Distinguishing traits: Forms clones with small, erect stems. Leaves are elliptic to circular, lack ciliate leaf margins (fine hairs along the edges), and may have a shiny or pilose (hairy) underside.
  • Known hybridizations: Hybridizes with S. arctica and possibly S. rotundifolia. Hybrids typically show mixed features like leaf glaucousness and flower density.
  • Read more on FNA: Salix polaris – Flora of North America

Salix reticulata (Net-leaf willow)

  • Distinguishing traits: Known for its net-like vein pattern on leaves which are oblong to circular and often very glossy on top. Stems can be trailing and may form clones.
  • Known hybridizations: Forms hybrids with S. arctica and S. barclayi, often displaying intermediate characteristics such as partially hairy ovaries and variation in leaf margin teeth.
  • Read more on FNA: Salix reticulata – Flora of North America

Salix rotundifolia (round-leaved willow or least willow)

  • Distinguishing traits: Forms clones with erect stems. Leaves are broadly elliptic or circular, often very glossy on top, and may have a ciliate margin. Typically displays a more robust growth form compared to other dwarf willows.
  • Known hybridizations: Known to hybridize with S. arctica, S. phlebophylla, and S. polaris, resulting in plants that often blend the parent species’ leaf characteristics and growth habits.
  • Read more on FNA: Salix rotundifolia – Flora of North America

Salix stolonifera (Creeping willow)

  • Distinguishing traits: Characterized by its creeping growth habit, forming mats or layers. Leaves are elliptic to circular and glossy on the upper surface, and the plants often have distinctive stolons (horizontal stems that root to form new plants).
  • Known hybridizations: Forms hybrids with S. arctica and S. barclayi, typically showing features of both in aspects like leaf texture and flower structure.
  • Read more on FNA: Salix stolonifera – Flora of North America

Photo captions will be updated as species are identified. This article will also be updated frequently.

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