Blepharodon crabronum (Apocynaceae: Asclepiadoideae), a new species from the pre-Cambrian serranias of eastern Bolivia D. J. Goyder 1 Summary. Blepharodon crabronum from the pre-Cambrian serranias of eastern Bolivia is described and illustrated. Key Words. Asclepiadaceae, Metastelmatinae, Santiago de Chiquitos, taxonomy. Introduction Blepharodon Decne. is a small South American genus in the Metastelmatinae (Apocynaceae: Asclepiadoideae) with 8 – 14 species recognised by different authorities (Fontella-Pereira & Marquete 1973, 1974; Morillo 1976). B. salicinum Decne. was excluded from the genus in these treatments, but subsequently returned to Blepharodon by Liede (1996). Molecular studies (Rapini et al. 2003, 2006; Liede-Schumann et al. 2005) have questioned the monophyly of Blepharodon as currently defined, suggesting that in future the genus may be restricted to the two species B. lineare (Decne.) Decne. and B. ampliflorum E. Fourn., which some authors have considered to be conspecific. However, the transfer of the remaining species to another genus has not been formally proposed. Species delimitation is problematic in much of the genus, particularly around the widely distributed and highly variable B. pictum (Vahl) W. D. Stevens complex. By contrast, a very distinctive species has recently been discovered by John Wood and myself in eastern Bolivia. The new species can be recognised by several discrete characters — its brittle, twiggy stems, the long- petiolate leaves, the highly fused corona with a long tooth arching towards the column, the short anther wings, and the slender follicle. The new species is formally described here. It is found only in crevices of the vertical rock pillars characteristic of several serranias in the region. However, while apparently suitable cliff faces are widespread in the region, the new species has so far only been found in a handful of localities. Blepharodon crabronum Goyder sp. nov. Ab omnibus ceteris speciebus Blepharodontis ramunculis multo fragilis, foliis longipetiolatis, lobis coronae lateraliter complanatis, margine exteriore loborum projecturam inflexam ferenti differt. Typus: Bolivia, Santa Cruz. Serrania de Santiago de Chiquitos, 25 Jan. 2001, Wood & Goyder 16956 (holotypus K; isotypi LPB, USZ). Glabrous perennial herb with brittle, stiff, some- what suffrutescent stems, corky at the base, erect at least initially but longer stems trailing, with very regular internodes, mostly short (< 1 cm long), nodes slightly swollen and with a conspicuous line of colleters on the interpetiolar ridges; latex white. Leaves opposite, petiolate, the petiole 1.5 – 2 cm long; lamina 3 – 5 × 0.4 – 1.6 cm, linear-lanceolate to oblong or elliptic, the apex somewhat attenuate or shortly mucronate, the base cuneate to rounded, both surfaces glabrous, but with a pair of colleters at the junction of the petiole with the base of the lamina. Inflorescences extra-axillary, with 2 – 3 nodding flowers arising singly or in pairs along a short axis, peduncle 2 – 6 mm long; bracts lanceolate, 1 – 2 mm long; pedicels 5 – 8 mm long. Sepals 1 – 2 mm long, ovate. Corolla maroon or brownish, globose in bud, campanulate at anthesis, c. 6 mm long, united into a tube for about half (Santiago) to one third (Chochís) of its length; lobes broadly triangular, acute or subacute, entirely glabrous (Santiago) or minutely puberulent adaxially towards the margin (Chochís). Corolline corona absent. Gynostegial corona of 5 staminal lobes, laterally compressed and cucullate, with a long appendage arising from the upper distal margin forming a tongue that arches towards the stylar head, the lower distal margin also extended into an irregularly toothed appendage, greenish cream or white. Anther wings c. 1 mm long. Pollinarium with corpusculum c. 0.25 mm long; translator arms slender, terete; pollinia pendant, c. 0.4 mm long, somewhat Accepted for publication October 2008. 1 Herbarium, Royal Botanic Gardens Kew, Richmond, Surrey, TW9 3AB, UK. KEW BULLETIN VOL. 64: 179–181 (2009) © The Board of Trustees of the Royal Botanic Gardens, Kew, 2009