This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Salix discolor Muhl. Neue Schrift. Ges. Nat. Fr. Berlin
A shrub or low tree, maximum height 250, trunk diameter 1°; twigs glabrous or pubescent; young leaves sometimes pubescent. Mature leaves usually glabrous, bright green above, glaucous and nearly white beneath, oblong, oblong-lanceolate or oblanceo-late, acute at both ends, irregularly serrate, or nearly entire, slender-petioled, 3'-5' long, 8"-18" wide; petioles 3"-12" long; stipules obliquely lanceolate or semicordate, commonly deciduous; aments unfolding much before the leaves, dense, the pistillate 1 1/2'-3 long in fruit; bracts persistent, brown-purple, villous; stamens 2; filaments glabrous; stigmas nearly sessile; capsule narrowly conic, tomentose, 2 1/2"-3' long, much longer than its pedicel.
In swamps or on moist hillsides, Nova Scotia to Saskatchewan, Delaware and Missouri. Consists of several races differing in pubescence and in leaf-forms. Wood soft, weak, yellow-brown; weight per cubic foot 27 lbs. Bog- or swamp-willow. March-May.
Salix humilis Marsh. Arb. Am. 140. 1785.
A shrub, 2 -8 tall, the twigs tomentose or pubescent, terete. Leaves mostly oblanceo-late, petioled, rather firm in texture, 2'-6' long, 4"-8" wide, acute at both ends or the lower broader and obtuse at the apex, sparingly denticulate, the margins slightly revolute, the upper surface dark green, dull, puberulent or glabrous, the lower densely and persistently gray-tomentose; petioles 2."-$" long; stipules obliquely lanceolate or ovate, acute, commonly persistent; aments unfolding much before the leaves, sessile, ovoid-oblong, dense, the pistillate about 1' long in fruit; stamens 2; filaments glabrous; stigmas nearly sessile; capsule narrowly conic, densely pubescent, much longer than its pedicel.
In dry soil, Newfoundland to Ontario, North Carolina, Tennessee and Kansas. Hybridizes with S. discolor. Low or bush-willow. April-May.
A tufted, slender shrub, 1°-2° tall, the twigs terete, puberulent, the roots long and thick. Leaves oblanceolate or linear-oblong, acute or obtusish, somewhat undulate, green and puberulent or glabrous above, persistently white-tomentose beneath, crowded, 1'-2' long, their margins revolute; petioles 1"-3" long; stipules minute, deciduous; aments expanding much before the leaves, dense, very small, few-flowered, sessile, the pistillate globose-ovoid and about ¥ long in fruit; bracts persistent; stamens 2; filaments glabrous; stigmas sessile or nearly so; capsule ovoid with a long, slender beak, tomen-tulose, about 3" long, much longer than its filiform pedicel.
In dry soil, Nova Scotia (?), Maine to Minnesota, Florida., Tennessee and Nebraska. March-April.