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Poplars — Part 3

The Black Cottonwood (P. trichocarpa, Hook.) is the giant of the genus, reaching 200 feet in height and 7 to 8 feet in trunk diameter. It is tall and stately, with a broad, rounded crown supported upon heavy upright limbs. One of the beautiful sights of the Yosemite Park is the autumnal gold of black cottonwood groves whose abundant foliage embowers the stream borders at the altitude of about 4,000 to 5,000 feet. The tree's range covers the coast plain and western slopes of mountains from Alaska to southern California. The largest trees are on the lowest levels. The dark rich green of the leaves gives this tree its name. They are ovoid, 3 to 4 inches long, with the finest of saw-toothed margins. The wood has come into extensive use for the manufacture of various woodenwares and for staves of sugar barrels.

Swamp Cottonwood (Populus heterophylla, Linn.)--Round-topped tree, 50 to 90 feet high. Bark red-brown, in narrow, loose plates; twigs red or grey, containing orange pith. Wood brown, light, compact. Buds resinous, ovate, with red scales. Leaves broadly ovate, 4 to 7 inches long, serrate, dark green with pale lining, when mature, covered with white tomentum as they unfold; petioles round, slender; yellow or brown in autumn. Flowers, March or April; staminate aments crowded, erect until blossoms open; anthers deep red; pistillate aments few-flowered, drooping. Fruit, May, aments 4 to 6 inches long; capsules few, 2 to 3-valved, 1/2 inch long, bell shaped. Preferred habitat, wet soil. Distribution, swamps from southern Connecticut to Georgia and Louisiana; north along Mississippi to Arkansas and Indiana.

The swamp cottonwood is variable in the base, apex and margin of its leaf. It may exhibit coarse or fine saw teeth, a blunt or sharp-pointed apex, a square or heart-shaped base. The conspicuous netted veins are always present, and the leaves are always large and broadly ovate, with slim, round petioles. The orange-coloured pith of the branchlets best distinguishes the tree from other poplars. The new shoots and the unfolding leaves are coated with white down. It often takes a whole summer to get rid of it.

The Acadians (probably) are responsible for the name langues de femmes, by which the tree is known in Louisiana. The mild calumny of Gerarde is thus perpetuated and extended to a species whose leaf stems are merely flexible, not flat at all! In the lumber trade the wood is known as "black poplar." It is dark brown in colour.