Volume 3 NOVON Nj||^ Number 2 1993 Lepidium tayloriae (Brassicaceae), a New Species from Chile Ihsan A. Al-Shehbaz Missouri Botanical Garden, P.O. Box 299, St. Louis, Missouri 63166-0299, U.S.A. ABSTRACT. Lepidium tayloriae from Atacama didymus, (3.4-)3.7-4 mm longus et latus, valvis alatis, (Region III), Chile, is described and illustrated. Its manifeste reticulato-venosis. relationship to L. pseudodidymum and /.. strictum Herbs annual, erect, 17-24 cm tall; branches is discussed, and its distinguishing characters from many, ascending, moderately to densely hirsute with these and other South American species are given. spreading trichomes to 0.5 mm long. Basal leaves not seen; lowermost cauline leaves pinnatisect, 2- Several South American species of Lepidium have 4 cm long, hirsute; petiole winged, 0.5-1.5 cm long, been discovered since Hitchcock’s (1945) revision, to 1 mm wide; lateral lobes 3-6, narrowly linear, and the total number, including this new species and 2-6 x 0.2-0.5 mm; rachis as wide as petiole; L. peruvianum Chacon (1990), bring the total es¬ uppermost leaves narrowly linear, entire, 1-4 cm timate of Al-Shehbaz (1989) to 52 species. The long, 0.3-1.5 mm wide. Inflorescences ebracteate South American species of Lepidium belong to sev¬ racemes, greatly elongated in fruit. Sepals ovate, eral complexes (e.g., L. abortanifolium Turczani- 0.6-1 x 0.3-0.5 mm, glabrous or rarely sparsely now, L. aletes Macbride, L. chichicara Desvaux, hirsute, purplish, scarious at margin, usually falling L. depressum Thellung, and L. meyenii Walpers), ofF after fruit maturation; petals filamentous, to 0.2 the taxonomy of which requires critical study. The mm long; stamens 2, the filaments white, ca. 0.6 limits of component species ol a given complex are mm long, the anthers ca. 0.2 mm long; nectar glands sometimes obscure. As shown below, however, the 4, toothlike, ca. 0.1 mm long. Fruiting pedicels 1.2- new species and its relatives are readily distinguished 2 mm long, erect, subappressed to rachis, narrowly from all the other South American lepidiums. winged, hirsute. Fruit suborbicular, subdidymous, (3.4-)3.7-4 mm long and wide, prominently retic¬ Lepidium tayloriae Al-Shehbaz, sp. nov. TYPE: ulate, winged, glabrous, emarginate at apex, trun¬ Chile. Atacama (Region III): Copiapo Province, cate-rounded at base; wing encircling all fruit, ca. between Huasco and Copiapo, ca. 20-25 km 0.6 mm wide at fruit apex; apical notch ca. 0.3 mm W of Totoral on the road to the coast, dry deep, ca. 0.6 mm wide; style absent; stigma entire. plains and hillside, 20°00'S, 70°50'W, 8 Oct. Seeds ovate, brown, ca. 2 x 1 mm; cotyledons 1991, C. M. Taylor, C. von Bohlen & A. incumbent. Marticorena 10804 (holotype, MO; isotype, Lepidium tayloriae, which is named after Char¬ CONC). Figure 1. lotte M. Taylor, one of the collectors of the holotype, Herba annua hirsuta 17-24 cm alta. Folia caulina is most closely related to the Argentinian L. pseu¬ infima pinnatisecta 2-4 cm longa, segmentis 0.2-0.5 mm dodidymum and the Chilean L. strictum (S. Wat¬ latis; folia superma anguste linearia integra, 1-4 cm longa, son) Rattan. These three species are readily distin¬ 0.3-1.5 mm lata. Flos sepalis ovatis 0.6-1 mm longis; guished from all of the other South American petalis filiformibus usque ad 0.2 mm longis; pedicellis fructiferis erectis 1.2-2 mm longis, anguste alatis. Fructus lepidiums by the prominently reticulate-veined fruits. suborbicularis, medio secus replum subconstrictus et sub- The new species differs from L. pseudodidymum Novon 3: 93-95. 1993. 94 Novon Volume 3, Number 2 Al-Shehbaz 95 1993 Lepidium tayloriae by its winged fruits (3.4-)3.7-4 mm long and wide, Acknowledgment. I am grateful to Roy Gereau erect fruiting pedicels, entire upper cauline leaves, for checking the Latin description. and sessile stigma. By contrast, L. pseudodidymum has wingless fruits 2-2.6 x 2.2-3 mm, arcuate- Literature Cited spreading fruiting pedicels, 2- or 3-pinnatifid or - Al-Shehbaz, I. A. 1989. Lepidium boelckei and L. pinnatisect upper cauline leaves, and styles ca. 0.17 jujuyanum (Brassicaceae), new species from Jujuy, mm long. It is separated from L. strictum by its Argentina. Ann. Missouri Bot. Card. 76: 1189-1192. Chacon, G. 1990. La maca (Lepidium peruvianum larger fruits with glabrous keel, toothlike nectar Chacon sp. nov.) y su habitat. Rev. Peru. Biol. 3: glands, entire upper cauline leaves, trichomes to 0.5 169-272. mm, and constricted fruit replum distinctly lower Hitchcock, C. L. 1945. The South American species than the valve surface. Lepidium strictum has of Lepidium. Lilloa 11: 75-134. smaller fruits (2.5 X 2 mm) with puberulent keel, linear nectar glands, pinnatisect upper leaves, tri¬ chomes to 0.3 mm, and raised fruit replum higher than the valve surface.