Monographs Details: Osmia odorata (L.) Sch.Bip.
Authority: Britton, Nathaniel L. Flora Borinqueña.
Description:Species Description - Santa Maria is the plentiful shrub of its family in Porto Rico, growing in both moist and dry parts of the island, at lower and middle elevations, ascending, in the mountains, to at least 600 meters elevation, and occurs also on the small island Vieques and Culebra; its profuse, clustered heads of small, white to blue flowers are conspicuous, blooming most freely in the winter months, the plant mainly inhabiting hillsides, banks and thickets; the flowers are pleasantly fragrant. This shrub is of very wide geographic distribution, nearly throughout the West Indies and continental tropical America, north to Florida and northern Mexico. It is the type species of Osmia, and is various in form and size of leaves, size of flower-heads, and color of flowers, appearing to be made up of several slightly differing races. Osmia (Greek, odorous), a genus established in 1866 by the Swiss botanist Schultz, designated in Latin, Bipontinus (Zweibruecken, his native town, in English Two Bridges) to distinguish him from another botanist of the same family name, is wholly composed of American shrubs, small trees and a few kinds of perennial herbs, perhaps as many as 100 species in all. They differ from the Eupatriums by the structure of the involucre of the flower-heads, this being cylindric, and having bracts overlapping in several series, numerous, striate, and firm in texture. They have opposite stalked leaves, and terminal, clustered heads of flowers without marginal rays (discoid). The receptacle of the flower-head is without scales or hairs (naked). The tubular corollas are 5-toothed, the anthers blunt; the style-branches are elongated. The fruits (achenes) are ribbed and bear a pappus of hair-like bristles. Osmia odorata (odorous) is upright, or half-climbing, usually much branched, from 1 to 3 meters high, more or less hairy. Its thin, toothed, ovate to lance-shaped, long-pointed leaves are from 5 to 15 centimeters long, 3-ribbed, green on both sides, their stalks from 1 to 4 centimeters long; the clusters of flower-heads are from 5 to 10 centimeters broad; the involucre is from 8 to 12 millimeters long, with about 4 series of smooth, shining bracts, all blunt, or the inner ones somewhat pointed. Individual shrubs have either white or blue flowers; in some districts white are prevalent, in others blue. Five other species of Osmia inhabit Porto Rico; of these, Osmia geraniifolia is also illustrated in this work.

Discussion:Santa Maria Bitter-bush Thistle Family Eupatorium odoratum Linnaeus, Systema Naturae, edition 10. 1205. 1759 Osmia odorata Schultz, Bipontinus, Pollichia 22-24: 251. 1866.