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..
Perennial branching herbs, some species shrubby, with rather small crenate-dentate or entire leaves, and small bracted pink or purple flowers, in dense terminal glomerules. Calyx ovoid or campanulate, villous in the throat, about 13-nerved, 5-toothed or more or less 2-lipped. Corolla-limb 2-lipped, the upper lip erect, emarginate or 2-lobed, the lower longer, spreading, 3-cleft. Stamens 4, didynamous, ascending; anthers 2-celled, the sacs divergent. Style 2-cleft at the summit; ovary deeply 4-parted. Nutlets ovoid or oblong, smooth. [Greek, mountain-joy.]
About 30 species, natives of the Old World, the following typical.
Origanum vulgare L. Sp. Pl. 590. 1753.
Perennial from nearly horizontal rootstocks, villous or hirsute; stem erect, slender, 1°-2 1/2° high. Leaves ovate, petioled, obtuse or subacute at the apex, rounded or subcordate at the base, crenate or entire, 1'-1 1/2' long, often with smaller ones, or short leafy branches, in their axils; flower-clusters often 2' broad; bracts purplish, ovate or oval, about equalling the nearly regularly 5-toothed calyx; corolla pink, purple or nearly white, longer than the calyx, the upper lobe broad; all four stamens, or the two longer, exserted.
In fields and waste places, Ontario to New Jersey and Pennsylvania. Naturalized from Europe. Native also of Asia. Called also organs, pot-marjoram. July-Sept.