A deciduous tree up to 60 ft high in the wild; young shoots quite free from down, ordinarily round, but angled when very vigorous; buds slender-pointed, glutinous. Leaves ovate to somewhat diamond-shaped, wedge-shaped to rounded at the base, slenderly pointed, finely round-toothed, 2 to 4 in. long (larger on vigorous shoots), half as much wide, shining green on both sides and but little paler beneath; leaf-stalks 1 to 21⁄2 in. long, slender. Catkins slender, not downy, up to 23⁄4 in long.
A native of western N. America from Montana and S. Dakota south to New Mexico and Arizona; discovered by Rydberg in Nebraska and described by him in 1893. It is probably not a good species but rather a hybrid complex resulting from the crossing of P. angustifolia with P. sargentii (or with P. fremontii in those areas where this species takes the place of P. sargentii). It differs from P. angustifolia and approaches the latter two species in its relatively broader leaves on longer, often slightly flattened, petioles and in other characters (Hitchcock et al., Vascular Plants of the Pacific Northwest, Pt 2, p. 34). Plants introduced to Kew in 1916 from the Arnold Arboretum made loose-habited trees with slender lax shoots, vividly green in leaf.