A bushy tree, 30°—40° high, with a short crooked often prostrate trunk occasionally 10′—12′ in diameter, stout contorted branches forming a round head, and branchlets green tinged with red and covered with dark red or slightly ferrugineous glandular-hispid hairs when they first appear, dark green and glabrous in their first winter, gradually turning bright red-brown in their second year, and ultimately gray tinged with red, the thin bark separating on branches four or five years old into persistent scales; more often a broad shrub, with many divergent twisted stems 10°—12° high. Winter-buds: leaf-buds conic, dark green, axillary, or terminal on barren shoots, with many closely imbricated scales, those of the inner ranks accrescent, increasing in length from the outer to the inner, and at maturity 1½′ long, ¼′ wide, gradually narrowed at base, and terminating at apex in a long slender point, light green, glabrous, closely held against the shoot by a resinous exudation from the glandular hairs, and in falling marking the branchlet with numerous conspicuous narrow remote scars persistent for three or four years. Bark of the trunk about 1/16′ thick, light red-brown, broken on the surface into small thin appressed scales. Wood heavy, hard, strong, rather brittle, close-grained, light clear brown, with thin lighter colored sapwood; occasionally made into the handles of tools and used as a substitute for boxwood in engraving. A decoction of the leaves is occasionally employed in domestic practice in the treatment of rheumatism.
Distribution. Nova Scotia, Mt. Chocorua, New Hampshire, and southward in New England and eastern New York and along the Appalachian Mountains to northern Georgia and westward to the northern shores of Lake Erie and to southeastern Ohio (Hocking and Fairfield Counties); rare at the north and an inhabitant of deep cold swamps in a few isolated stations; more abundant on the mountains of western Pennsylvania, becoming exceedingly common farther south and occupying the steep banks of streams up to altitudes of 3000°; of its largest size on the high mountains of eastern Tennessee and the Carolinas, and here often forming thickets hundreds of acres in extent.
Often cultivated as an ornament of parks and gardens in the United States, and in Europe, and one of the parents of a number of distinct and beautiful hybrids.
3. KALMIA L.
Trees or shrubs, with scaly bark, terete branchlets without a terminal bud, minute axillary leaf-buds, elongated axillary inflorescence-buds covered by imbricated scales, and fibrous roots. Leaves ovate-oblong or linear, short-petiolate, with flat entire margins, coriaceous, persistent or deciduous in one species. Flowers on slender pedicels bibracteolate at the base, from the axils of foliaceous coriaceous ovate or acute persistent bracts, in axillary umbels; calyx 5, rarely 6-parted, the divisions imbricated in the bud, persistent under the fruit; corolla 5, rarely 6-lobed, rose-colored, purple, or white, saucer-shaped, with a short tube and 10 pouches just below the 5 or 6-parted limb, the lobes ovate, acute, before anthesis prominently 10 or 12-ribbed from the pouches to the acute apex of the bud, the salient keel of the ribs running to the point of the lobes and to the sinuses; stamens 10, shorter than the corolla; filaments filiform; anthers oblong, each cell opening by a short apical oblong longitudinal pore, at first free in the bud, the filaments then erect, later received in the pouches of the corolla, the filaments becoming bent back by its enlargement and expansion, straightening elastically and incurving on the release of the anthers, and in straightening discharging the pollen-grains; disk prominently 10-lobed; ovary subglobose, 5-celled; style filiform, exserted, crowned with a capitate stigma; ovules numerous in each cell, inserted on a 2-lipped placenta, pendulous or spreading from near the top of the thin columella, few-ranked, anatropous. Fruit a woody many-seeded globose slightly 5-lobed 5-celled capsule, tardily septicidally 5-valved, the valves crustaceous, ultimately opening down the middle by a narrow slit and separating from the persistent placenta-bearing axis. Seeds oblong or subglobose, minute; seed-coat crustaceous or membranaceous; embryo in fleshy albumen, terete, near the hilum; radicle erect, rather shorter than the oblong cotyledons.
Kalmia with six species is North American and Cuban, one species occasionally becoming under favorable conditions a small tree.
The generic name is in honor of the Swedish traveler and botanist, Peter Kalm (1715—1779).
1. [Kalmia latifolia] L. Laurel. Mountain Laurel.
Leaves sometimes in pairs or in 3’s, conduplicate in the bud, each leaf in the bud inclosed by the one immediately below it, oblong or elliptic-lanceolate, acute or rounded and tipped at apex with a callous point, and gradually narrowed at base, rarely oval to oblong-obovate and rounded at ends (f. obtusata Rehd.), when they unfold slightly tinged with pink and covered with glandular white hairs, and at maturity thick and rigid, dark rather dull green above, light yellow-green below, 3′—4′ long and 1′—1½′ wide, with a broad yellow midrib and obscure immersed veins; beginning to fall during their second summer; petioles stout, terete or slightly flattened, about ⅔′ in length. Flowers opening from early in April in southern Mississippi to the 20th of June at the north; inflorescence-buds appearing in the autumn from the axils of upper leaves, beginning to lengthen with the first warm days of spring and usually developing 2 or several lateral branches, the whole forming a compound many-flowered corymb of numerous crowded fascicles more or less covered with dark scurfy scales, 4′—5′ in diameter, and overtopped at the flowering time by the leafy branches of the year; flowers nearly 1′ in diameter, on long slender red or green pedicels covered with glandular hairs, and furnished at base with 2 minute acute bractlets, developed from the axils of acute persistent bracts sometimes ⅓′ long; calyx divided nearly to the base into narrow acute thin green lobes; corolla white (f. alba Rehd.), rose-color, or deep pink (f. rubra Rehd.) viscid-pubescent, marked on the inner surface with a waving dark rose-colored line and with delicate purple penciling above the sacs, rarely with a broad purple or chocolate-colored band (f. fuscata Rehd.). Fruit ripening in September, crowned with the persistent style, 3/16′ in diameter, and covered with viscid hairs, remaining on the branches until the following year; seeds oblong, light brown, scattered by the opening of the valves.