Monographs Details: Pentarhaphia albiflora Decne.
Authority: Britton, Nathaniel L. Flora Borinqueña.
Description:Species Description - The endemic species of insular floras are always of special interest to the naturalist, providing features for speculation upon their origin, and discussion of the nearest related species existing in other lands. The Porto Rico Pentarhaphia common on hillsides, river-banks and woodlands at lower and middle altitudes in this island, is one of the 30 species of its genus distributed through the West Indies and continental tropical America. They are shrubs, or small trees, with rather thick, narrow or broad leaves, the flowers in long-stalked clusters, or solitary. The calyx is adnate to the ovary, and usually has 5 narrow teeth; in our species and in others it has 5 ribs, whence the generic name, derived from the Greek, and given by the English botanist Lindley in 1827. The corolla is irregularly bell-shaped or narrower, with an oblique, 5-lobed and 2-lipped limb. There are 4 stamens, with elongated, slender filaments and short, coherent anthers; the style is also long and slender. The capsular fruit about as long as the calyx-tube, contains many small seeds. Pentarhaphia albiflora is usually a shrub 2 or 3 meters high, but occasionally forms a tree up to about 5 meters high; its branches are smooth and slender. Its leaves are oblong or elliptic, sometimes broader above the middle than below, smooth, pointed, with continuous or slightly toothed margins, rather firm in texture, from 4 to 10 centimeters long, on stalks 7 to 15 milimeters long. The flowers are borne 2 to 4 together, at the end of a slender stalk which is longer than the leaves, and each flower has a slender stalk; the 5-ribbed calyx-tube is inversely conic and from 7 to 10 millimeters long, with 5 awl-shaped lobes about as long, or a little longer; the corolla is about 2 centimeters long with a 2-lobed limb about as wide, and is remarkably various in color, white, yellow, brownish, or mottled, the limb sometimes purplish, a white-flowered race having suggested the specific name albiflora. The ripe fruit is a little longer than the coherent tube of the calyx, its tip somewhat hairy. Our illustration was first published in "Addisonia", plate 448, December, 1928.

Discussion:Porto Rico Pentarhaphia Arbol de Navidad Gesneria Family Pentarhaphia albiflora Decaisne, Annales des Sciences Naturelles III. 6: 101. 1849.