Key to the Coastal Willows (Salix) of Northwestern California
Gordon Leppig,
California Department of Fish and Game
Draft March 13, 2003

This key covers native and naturalized willows in Del Norte, Humboldt, and Mendocino Counties occurring below 300 meters in elevation and within 10 kilometers of the coast. This key includes male, female and vegetative characters, but in many cases flowers (male or female) and vegetative characters will be needed for proper identification. Please send suggestions and additional species to gleppigdfg.ca.gov.

  • Bud scale margins overlapping, tip acute, pointed; ovary glabrous; stamens 5 Salix laevigata
  • Bud scale margins fused, tip blunt, rounded; ovary glabrous or hairy; stamens 1-2 (except S. lucida with 3-5 stamens)
    • Large tree with single trunk or shrub with trucks and branches bright yellow; petiole and leaf base edges glandular
      • Twigs bright yellow; shrub or small tree, multi-stemmed, <5 m tall; stamens 2 White willow - S. alba
      • Twigs brownish; large tree, single trunk, 5-10 m tall; stamens 3-5 Shining willow - S. lucida ssp. lasiandra
    • Shrub to small tree, rarely with single trunk, branches and trunks brownish, reddish, to yellow, not bright yellow; Petiole and leaf base edges not glandular;
      • Lvs linear, usually >10x longer than wide; petiole <5mm; female flower bract deciduous catkins appearing with or after lvs Narrow-leaved willow - S. exigua
      • Lvs elliptic, lanceolate, oblong to obovate, usually <5x longer than wide; petiole usually >1cm; catkins appearing with or before lvs; female flower bract persistent
        • Older lvs very leathery; Summer twigs and lvs with prominent red galls; ovary glabrous to tomentose; restricted to coastal dunes and adjacent wetlands Coastal willow - S. hookeriana
        • Older lvs soft to firm, not leathery; Summer twig and lf galls absent or brown if present; ovary glabrous or long silky to tomentose; various coastal and inland habitats
          • Ovary glabrous; filaments two, fused; nectary cylindrical, rod-shaped Arroyo willow - S. lasiolepis
          • Ovary long silky; filaments one or if two, not fused; nectary cylindrical or square-stubby
            • Lf underside persistently luxuriously velvety, hairs white; catkins on leafy braches; Ovary 2-6 mm; stamens 1; nectary cylindrical, rod-shaped Sitka willow - S. sitchensis
            • Lf underside grayish and waxy, variously pubescent, if velvety then not luxurious, hairs use mixed white and rusty; catkins sessile on naked branches; ovary (4) 5-9 mm long; stamens 2; nectary square-stubby Scouler's willow - S. scouleriana

Last modified  03/29/03 02:33 EST