New Taxa and Combinations in Eleutherococcus (Araliaceae) from Eastern Asia

Abstract

While preparing a monographic study of Eleutherococcus, we discovered the three new taxa, E. brachypus var. omeiensis, E. huangshanensis, and E. pseudosetulosus, described here. In addition, three new combinations, E. divaricatus var. chiisanensis, E. pilosulus, and E. pubescens, are proposed. Eleutherococcus Maximowicz (1859, emend. C. H. Kim & B.-Y. Sun) is an endemic Asian genus with about 35 species distributed mainly in northeastern Asia including China, Korea, and Japan, with some members also extending to southwestern Asia (Kim, 1997). The genus Acanthopanax (Decaisne & Planchon) Witte was initially recognized as a subgenus of Panax L. by Decaisne and Planchon (1854) and raised to generic rank by Witte (1861). Harms (1894) combined the two genera, and adopted the name Acanthopanax, which has since been widely used by many botanists. However, Acanthopanax does not have priority and is therefore illegitimate under current ICBN nomenclature (Greuter et al., 1994). Some recent authors (e.g., Hu, 1980; Ohashi, 1987; Hsu & Pan, 1993) have therefore transferred taxa from Acanthopanax to Eleutherococcus. Plants of Eleutherococcus are shrubs and are characterized by the presence of prickles, five-merous flowers with two to five carpels, and palmately compound leaves. The genus as a whole is highly variable resulting in much taxonomic confusion (Kim, 1997). For example, E. koreanus Nakai was distinguished from E. senticosus (Ruprecht & Maximowicz) Maximowicz based on its unarmed twigs. However, examination of specimens from various regions has shown this character to be merely included within the limits of natural variation among individuals. While preparing a monographic study of Eleutherococcus, we found three new taxa and describe them here: E. brachypus var. omeiensis, E. huangshanensis, and E. pseudosetulosus; three new combinations are also made: E. divaricatus var. chiisanensis, E. pilosulus, and E. pubescens. Eleutherococcus brachypus (Harms) Nakai var. omeiensis C. H. Kim & B.-Y. Sun, var. nov. TYPE: China. Sichuan: Omei Hsien, Mt. Omei, 10 Oct. 1940, T C. Lee 3794 (holotype, US; isotype, A). Foliola 3, terminalia foliola elliptica, glabra; terminales petioluli ca. 1 cm longi, glabri. Flores cum pedicellis articulatis. A hermaphroditic shrub to 2 m tall; stems erect, glabrous. Leaves 3-foliolate, leaflets elliptic, somewhat chartaceous, glabrous on both surfaces, secondary veins 3 to 5 pairs, the apex obtuse or acuminate, the margin entire, the base cuneate; petiole 0.5 cm long, glabrous; terminal leaflets 2-4 x 11.5 cm, petiolule relatively long, ca. 1 cm; lateral leaflets somewhat smaller than terminal ones, sessile or short-petiolulate. Inflorescence of umbels arranged in a simple cyme at the end of long branches of the current year's growth, rarely at the end of short branches, glabrous; pedicel articulated at uppermost part, 1-1.5 cm long, glabrous. Calyx 5toothed; petals 5; stamens 5; carpels 5, style united into a single column, stigma indistinctly 5-lobed, ca. 1 mm long; ovary 2 mm long. Fruit unknown. This variety is thus far known only from Mt. Omei, Sichuan, China, from which the epithet was derived. The typic variety occurs in Gansu, Shanxi, and Shaanxi in China. Eleutherococcus brachypus var. omeiensis differs from other members of the genus by its articulation in the uppermost part of the pedicel. This variety is also distinguished from the typic variety in having a long (ca. 1 cm) petiolule on the terminal leaflet. Other features are the same and hence we recognize it as a variety of E.