Your help is appreciated. We depend on donations to help keep this site free and up to date for you. Can you please help us?


Native Plant Trust: Go Botany Discover thousands of New England plants


See list of 4 species in this genus

Reference: Reznicek et al. (2002).

  • 1a. Hypogynium vestigial, therefore, the achene base ± continuous with the achene body and without a basal zone of different color and texture; leaf blades 0.5–2 mm wide; plants annual, from fibrous roots
  • 1b. Hypogynium present, therefore, the achene with a distinct basal zone of different color and texture; leaf blades 1–9 mm wide; plants perennial, from firm, nodulose rhizomes or annual with fibrous roots in S. reticularis
    • 2a. Achene body lustrous and smooth; hypogynium unlobed and without tubercles, densely beset with minute, white to light brown papillae; leaf blades 3–9 mm wide
    • 2b. Achene body dull to sublustrous, either pitted or papillate-verrucose; hypogynium either lobed or with tubercles, without minute papillae; leaf blades 1–3.5 mm wide
      • 3a. Hypogynium with 3 oblong lobes, without tubercles; achene body reticulate-patterned with polygonal pits; inflorescence a panicle of clusters, with visible branches
      • 3b. Hypogynium without lobes, bearing 6 globose tubercles arranged in 3 pairs; achene body papillate-verrucose, these projections sometimes arranged to provide the appearance of irregular transverse ridges; inflorescence a dense terminal cluster, sometimes with 1 or 2 axillary clusters as well

Show All Couplets

 Show photos of:   Each photo represents one species in this genus.