This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", 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..
Leafy branching herbs, with broad dentate leaves, and rather small white or yellowish axillary clustered somewhat secund flowers. Calyx oblong-campanulate, deflexed in fruit, 13-nerved, nearly naked in the throat, 2-lipped; upper lip flat, 3-toothed, the lower 2-parted. Corolla exserted, its tube curved-ascending, enlarged above, naked within, the limb 2-lipped; upper lip erect, emarginate; lower lip 3-cleft, spreading. Stamens 4, didynamous, connivent and ascending under the upper lip of the corolla; anthers 2-celled, their sacs divaricate. Ovary deeply 4-parted; style 2-cleft at the summit, the lobes subulate. Nutlets ovoid, smooth. [Greek, bee.]
About 4 species, natives of Europe and western Asia, the following typical.
Melissa officinalis L. Sp. Pl. 592. 1753- Perennial, pubescent; stem rather stout, erect or ascending, l°-2 1/2° high. Leaves ovate, petioled, mostly obtuse at both ends, sometimes cordate, pinnately veined, coarsely dentate or crenate-dentate, 1'-2 1/2' long; flowers several in the axillary clusters; pedicels shorter than the calyx; calyx about 3" long, the teeth of its lower lip slightly exceeding those of the upper; corolla white, 5-7" long.
In waste places, thickets and woods, Maine to Georgia, West Virginia, Missouri and Arkansas, also in Oregon and California. Naturalized from Europe. Plant lemon-scented. Balm-leaf or -mint. Honey-plant. Pimentary. Goose-tongue. Dropsy-plant. Lemon-lobelia. Sweet-mary. June-Aug.