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..
A perennial erect herb, the stem somewhat woody at the base, with narrow, entire leaves, and small bracted purple or blue flowers, in dense clusters in the upper axils, and forming elongated terminal more or less interrupted spikes. Calyx tubular, 15-nerved, about equally 5-toothed, not hairy in the throat. Corolla-limb 2-lipped, the upper lip erect, emarginate, the lower spreading, 3-cleft, the middle lobe 2-lobed. Stamens 4, didynamous, the 2 longer ones exserted, divergent; anthers 2-celled, the sacs divaricate. Ovary deeply 4-parted; style 2-cleft at the summit. Nutlets ovoid, somewhat 3-sided, nearly smooth. [Greek, an aromatic herb.]
A monotypic genus of Europe and Asia.
Hyssopus officinalis L. Sp. Pl. 569. 1753.
Stems usually several together from the woody base, slender, strict, puberulent, simple or branched, 1°-3° high, the branches upright or ascending. Leaves linear to oblong, sessile or very nearly so, firm, acute at both ends or the lower obtuse at the apex, puberulent or glabrate, faintly veined, 1 1/2'-2' long, 1"-3" wide, sometimes with smaller ones or short leafy branches in their axils; spike sometimes 1-sided, dense, 1/2'-1' broad; pedicels short, puberulent; outer bracts as long as the calyx; calyx-teeth lanceolate, acute, one-fourth to one-third as long as the tube; corolla 4"-5" long, its tube exceeding the calyx.
Along roadsides and in waste places, Ontario and Maine to North Carolina, and on the Pacific Coast. Naturalized from Europe. June-Sept.