Raup willow

Plants 1.2-1.8 m, not clonal. Stems erect; branches gray-brown, glabrous; branchlets yellow-brown, glabrous. Leaves: stipules foliaceous; petiole 5-9 mm; largest medial blade narrowly elliptic, 32-58 × 12-19 mm, 2-3.3 times as long as wide, base cuneate or convex, margins slightly revolute, entire, apex acute to acuminate, abaxial surface glabrous, adaxial slightly glossy, glabrous; proximal blade margins shallowly serrulate; juvenile blade glabrous. Catkins: staminate 17.5-42 × 5-13 mm, flowering branchlet 6-7 mm; pistillate moderately densely flowered, stout, 20-40 × 6-12 mm, flowering branchlet 4-7 mm; floral bract tawny or bicolor, 1.3-2.5 mm, apex rounded, entire, abaxially glabrous. Staminate flowers: abaxial nectary 0.3-0.8 mm, adaxial nectary narrowly oblong, 0.6-1 mm, nectaries distinct; filaments distinct, glabrous; anthers ellipsoid, shortly cylindrical, or globose, 0.4-0.7 mm. Pistillate flowers: abaxial nectary absent, adaxial nectary narrowly oblong or oblong, 0.5-1.1 mm, equal to or longer than stipe; stipe 0.4-1.2 mm; ovary pyriform, usually glabrous, rarely puberulent, beak slightly bulged below styles; ovules 12 per ovary; styles 0.6-0.8 mm; stigmas flat, abaxially not papillate with rounded tip, or broadly cylindrical, 0.3-0.5 mm. Capsules 4.4-8 mm.

Flowering late Jun. Thickets in moist, open forests, gravel floodplains; of conservation concern; 800-1500 m; Alta., B.C., N.W.T., Yukon.

Salix raupii resembles glabrous S. glauca var. villosa. Thin-layer chromatography of leaf phenolics in S. raupii revealed a pattern similar to those of S. glauca vars. villosa and acutifolia and S. athabascensis (G. W. Argus, unpubl.). Based on overall similarity, its nearest neighbors are S. glauca, in a broad sense, and S. athabascensis (Argus 1997). The sectional placement of this species is uncertain. It is placed here in sect. Myrtilloides because it clusters with S. athabascensis, but it is evidently close to S. glauca and may be a species of intersectional hybrid origin.