Monographs Details: Osmia geraniifolia (Urb.) Britton & P.Wilson
Authority: Britton, Nathaniel L. Flora Borinqueña.
Description:Species Description - No popular names for this endemic shrub of Porto Rico are recorded. It is a localized species, restricted in distribution to mountains of the central districts, inhabiting banks and hillsides, usually in thickets, sometimes in forests, often forming colonies; we have observed it, or have records of its occurence, from the vicinity of Aibonito westward to Utuardo, at no point lower than about 600 meters elevation. The species differs from all its Porto Rican relatives in having deeply lobed leaves; this lobing is, however, various in character, some colonies having leaves much less lobed than others; we studied one of these on a bank along the Villalba-Ciales road south of the Divisorio in 1930 and 1931. For an account of the genus Osmia we refer to our description of Osmia odorata. Osmia geranifolia (leaves like those of some Geraniums) is a densely hairy shrub, about 1.5 meters high, or lower. The leaves are ovate in outline, from 2 to 6 centimeters long, usually deeply 3-lobed or 3-cleft and the segments again lobed or toothed, the lobes blunt; or the leaves sometimes merely 3-lobed with the middle lobe larger than the lateral ones; the leaf-stalks are about 2 centimeters long, or shorter; the lower leaves sometimes have 2 or more small, toothed or untoothed leaves in their axils. The clusters of flower-heads are about 3 to 7 centimeters broad; the flowers blue. The involucre is 7 or 8 millimeters long, its hairy, blunt bracts imbricated in 4 or 5 series; the corollas are slender, the styles long-exserted. The achenes are minutely hairy. Our illustration was first published in "Addisonia", plate 552, May, 1932.

Discussion:Geranium-leaved Osmia Thistle Family Eupatorium geranifolium Urban, Symbolae Antillanae 1: 458. 1899. Osmia geranifolia Britton and Wilson, Scientific Survey of Porto Rico and the Virgin Islands 6: 288. 1925.