Browallia americana L.

Erect or straggling herb to 70 cm tall; stems mostly green, puberulent with short, mostly forward directed, simple or glandular hairs. Leaves ovate, to 5 cm long, acute or acuminate apically, truncate, obtuse or short acuminate basally, margins entire or nearly so, above glabrous or with scattered simple hairs on the lamina, beneath puberulen.t on the major veins; petiole half as long as the leaf or less. Pedicels erect, 3-5 mm long, puberulent, with very fine forward directed, sometimes glandular hairs. Flowers showy, the calyx 5-10 mm long, glabrate or with scattered larger, simple, often glandular hairs on the outside, lobed about 1/4 the way down, the lobes pointed or rounded, the tube strongly angled becom-ing broadly cupular in fruit; corolla blue, mauve, purple or white, salverform, the tube 12-15 mm long, puberulent, the limb 10-14 mm across, puberulent on the ribs beneath; stamens 4, filaments of the upper pair flattened and broadened into a curved, strap-like structure, densely pilose with dendrictic, colored hairs, the lower pair only slightly flattened and sparsely pilose, the anthers yellow; ovary 1-1.5 mm long, appressed pubescent on top with simple, several-celled hairs, stigma 2-lobed and impressed beneath by the anthers to assume a 4-lobed appear-ance. Fruit an erect, many-seeded capsule immersed in the chartaceous calyx. Although attempts have been made to recognize distinct species within the variation displayed by Browallia americana, an examination of a wide range of plants from South and Central America shows only slight polymorphism in a single wide-ranging species which grows under considerable diversity of eco-logical conditions. Characters which vary most noticeably are corolla size, the pubescence, especially its density and its tendency to become glandular or viscid, and a tendency for the calyx lobes to become expanded and sub-foliar at the tips as fruit develops. None of these variations displays a pattern worthy of recog-nition at the species level. Plants with an especially heavy complement of gland-ular hairs have been known as B. viscosa and may represent a distinct taxon. No other synonyms cited above apply to the glandular form. There is in Panama, at least, however, a seeming altitudinal stratification with respect to flower color. At elevations above about 1,500 m, flowers are mostly very deep blue or purple with a small but conspicuous white eye. From about 1,500 m down to sea level, flowers are mostly violet, mauve or light blue with a white or a white and yellow eye. At about 600 m elevation, one large colony was found with consistently white flowers. These plants have a yellow eye, and upon opening the corolla, the pubescence on the filaments is found to be purplish. This colony is about 2 miles above Paseo la Canoa in Chiriqui Province (D'Arcy 5314). Such white-flowered plants may be known as fo. alba Stehle.