Lepidium beckii (Brassicaceae), a New Species from Bolivia

Abstract

Lepidium beckii, a shrubby new spe- cies from Depto. La Paz (Bolivia), is described and illustrated. Its relationship to L. philippianum and L. quitense is discussed. Of the world's ca. 180 species of Lepidium L., some 52 species are restricted to South America (Al-Shehbaz, 1993). All except two of the South American species are herbaceous. A third woody species, L. beckii, is described below, and the char- acters that distinguish it from the other two woody members, L. quitense Turczaninow and L. philip- pianum (Kuntze) Thellung, are discussed. Suffrutex omnino puberulus. Folia sessilia, anguste li- nearia, (0.5-)1-1.5(-2.5) cm longa, 0.5-1.2 mm lata. Flos sepalis oblongis, 1.7-2 mm longis, 0.9-1.1 mm latis, an- guste membranaceo-marginatis; petalis albis, anguste ob- lanceolato-spathulatis, 2.5-3 mm longis, 0.5-0.7 mm la- tis; staminibus 4. Silicula oblonga vel ovato-oblonga, 4-5 mm longa, 3-3.5 mm lata, puberula; stylo persistente 0.5- 0.7 mm longo. Subshrubs, all parts except petals and filaments horizontally puberulent with trichomes 0.05-0.1 mm long. Stems 10-15 cm tall, woody along entire growth of previous years, 1-2 mm wide, slightly striate. Leaves all cauline, not forming rosettes, narrowly linear, (0.5-)1-1.5(-2.5) cm long, 0.5-1.2 mm wide, sessile, somewhat fleshy, entire, widest at or near base, acute at apex, often strongly con- cave adaxially, ascending to subappressed on stem, puberulent along both surfaces. Inflorescences few- flowered, ebracteate corymbose racemes, elongated in fruit. Fruiting pedicels flattened, ascending to divaricate, 3.5-5 mm long. Sepals oblong, ascend- ing, 1.7-2 mm long, 0.9-1.1 mm wide, not saccate, membranous margin and apex 0.2-0.4 mm wide, apex obscurely denticulate. Petals white, narrowly oblanceolate-spatulate, 2.5-3 mm long, 0.5-0.7 mm wide, not clawed, gradually attenuate to base, apex obtuse. Stamens 4; filaments white, distinctly dilated at base, 2-2.6 mm long; anthers ovate, 0.5- 0.6 mm long. Silicles oblong to ovate-oblong, 4--5 mm long, 3-3.5 mm wide; valves puberulent, keeled, not veined; apical notch 0.1-0.2 mm deep; style exserted from apical notch, 0.5-0.7 mm long, sparsely puberulent basally; stigma entire. Seeds reddish brown, oblong, ca. 2 x 1 mm; cotyledons accumbent.