Trees or shrubs with dioecious flowers, both sorts in catkins, one under each scale of the catkin. No calyx. Fruit 1-celled, many-seeded, the seeds furnished with tufts of down. (Part I., section 74, for description of typical flowers.) This Order comprises the Willows and Poplars.
1. Salix. Trees with mostly long and pointed leaves and slender branches. Bracts or scales of the catkins not toothed. Stamens mostly 2 under each bract, but in one or two species as many as 5 or 6. Stigmas short. Catkins appearing before or with the leaves.
2. Pop'ulus. Trees with broad and more or less heart-shaped leaves.
Bracts of the catkins toothed or cut at the apex. Stamens 8-30, or even more, under each scale. Stigmas long. Catkins long and drooping, preceding the leaves.
* Catkins borne on the ends of the short lateral leafy branchlets. Scales yellowish, deciduous. Filaments hairy below. Trees or large shrubs, with taper-pointed leaves.
1. S. nigra, Marshall. (Black Willow.) A tree with a roughish black bark, growing along streams. Leaves narrowly lanceolate, tapering at each end, serrate, smooth, green on both sides. Stamens 3-6. Ovary short-pedicelled. Sterile catkins long and narrow.
2. S. amygdaloi'des, Anders. A tree with lanceolate or ovate-lanceolate leaves, pale or glaucous beneath, and with long slender petioles. Fertile catkins becoming very loose from the lengthening of the pedicels. Stamens 3-6. - N.W.
3. S. lu'cida, Muhl. (Shining Willow.) A shrub or small bushy tree, growing along streams. Leaves ovate-oblong or narrower, with a long tapering point, shining on both sides, serrate. Stamens most 5. Scales of catkins dentate, hairy at the base. Sterile catkins densely-flowered, showy.
4. S. frag'ilis, L. (Crack Willow.) A tall and handsome tree. Leaves lanceolate, long-pointed, pale or glaucous beneath, 3-6 inches long. Stamens mostly 2, rarely 3-4. Capsule short-pedicelled. - Atl. Prov.
5. S. alba, L., var. Caeru'lea, Smith. Leaves ashy-gray or white both sides, except when old, lanceolate, long and slender-pointed. Stamens mostly 2. Pods sessile or nearly so. Old leaves smooth, glaucous beneath, dull bluish-green. - Cultivated in many places.
6. S. longifo'lia, Muhl. (Long - leaved Willow.) A shrub or small tree, varying greatly in size, growing along streams in sandy or gravelly places, and often forming dense clumps Leaves linear-lanceolate, very long, tapering towards both ends, nearly sessile, serrate with a few spreading teeth, grayish-hairy when young. Stamens 2.
* * Catkins lateral or terminal. Scales coloured at the tip, persistent. Stamens 2, the filaments not hairy. Shrubs or small trees.
- Ovaries woolly.
7. S. dis'color, Muhl. (Glaucous Willow.) A shrub or small tree, 8-15 feet high, growing in low grounds and along streams. Leaves lanceolate or ovate-lanceolate, irregularly toothed in the middle of the margin, entire at each end, smooth and bright green above, white-glaucous beneath, when young. Stipules moon-shaped, toothed. Catkins sessile, very early in spring before the leaves. Scales very dark and hairy.
Var. erioceph'ala, Anders., has densely-flowered and very silky catkins, and the leaves somewhat pubescent even when old.
8. S. liv'ida, Wahl. Var. occidenta'lis, Gray. (S. rostrata, Rich., in Macoun's Catalogue.) (Livid Willow.) A good-sized shrub, chiefly in moist situations. Leaves oblong or obovate-lanceolate, barely toothed, downy above, very veiny, hairy and glaucous beneath. Stipules semi-lunar, toothed. Ovary at length raised on a very slender stalk Catkins appearing with the leaves.
9. S. hu'milis, Marshall. (Prairie Willow.) A grayish shrub, 3-8 feet high, growing usually in dry or barren places. Leaves oblanceolate, pointed, the lowest obovate, slightly downy above, thickly so beneath. Stipules semi-ovate or moon-shaped, with a few teeth, shorter than the petioles. Catkins ovoid, sessile, before the leaves, naked at the base. Scales dark red or brownish.
10. S. petiola'ris, Smith. (Petioled Willow.) A low shrub on sandy river banks. Leaves narrowly lanceolate, finely and evenly serrate, silky-gray or glaucous beneath, smooth above. Catkins with a few small leaf-like bracts at the base. Scales of the fertile catkins acute, very hairy. Ovary tapering, silky, stalked.
11. S. can'dida, Willd. (Hoary Willow.) A shrub not more than 3 or 4 feet high, growing in bogs and wet places; the twigs and leaves clothed with a web-like wool, giving the whole plant a whitish aspect. Leaves lanceolate, narrow, with somewhat revolute margins. Stipules small, lanceolate, toothed. Catkins cylindrical. Anthers red.
+ + Ovaries glabrous.
12. S. cordata, Muhl. (Heart-leaved Willow.) A shrub or small tree, growing in wet grounds. Leaves lanceolate, not always heart-shaped, sharply serrate, smooth, green both sides. Catkins cylindrical, rather slender, leafy-bracted at the base, the sterile ones silky. Var. angustata has long narrow leaves.
13. S. balsamif'era, Barratt. A small much-branched shrub. Young twigs shining-chestnut on the sunny side. Leaves ovate-lanceolate, usually slightly cordate at base, at first very thin and of a reddish colour, at length rigid, dark-green above, and paler and conspicuously reticulate-veined beneath, slightly serrate, with slender petioles. Sterile catkins very silky, with a few bracts at the base; fertile catkins leafy-peduncled, becoming very loose in fruit. Capsules long-pedicelled. - Swamps, Atl. Prov. and northward.
14. S. myrtilloi'des, L. Low shrub, 1-3 feet high. Leaves elliptic-obovate, an inch long, entire, smooth, somewhat coriaceous when mature, revolute, reticulated, pale or glaucous beneath. Fertile catkins loosely few-flowered, on long leafy peduncles. Capsules glabrous, on slender pedicels. - Peat-bogs.
1. P. tremuloi'des, Michx. (American Aspen.) A tree with a greenish-white bark, and roundish heart-shaped leaves, continually in a state of agitation, due to the lateral compression of the petiole, and the consequent susceptibility of the leaf to the least motion of the air. Teeth of the leaves small.
2. P. grandidentata, Michx., (Large-toothed Aspen) has roundish ovate leaves with large irregular sinuate teeth.
3. P. balsamif'era, L. (Balsam Poplar.) A tall tree, growing in swamps and along streams; the large buds varnished with resinous matter. Leaves ovate, tapering, finely serrate, whitish beneath. Stamens very numerous.
Var. can'dieans, Gray, (Balm of Gilead) has broader and more or less heart-shaped leaves.
4. P. monilif'era, Ait. (Cottonwood.) A tree with broad deltoid leaves, slightly heart-shaped, serrate with incurved teeth. Young branches slightly angled, at length round. Fertile catkins very long, the scales cut-fringed, not hairy. - Along the main line of the Grand Trunk Railway.