Cardiospermum cuchujaquense (Sapindaceae), a New Species from Sonora, Mexico

Abstract

A new species, Cardiospermum cuchujaquense from Sonora, Mexico, is described and illustrated. The new species belongs to C. sect. Carphospermum, which is characterized by the presence of chaffy or scaly trichomes. With the discovery of C. cuchujaquense, a pattern of disjunct distribution is documented for C. sect. Carphospermum. RESUMEN. En el presente articulo se describe y se ilustra una nueva especie de Cardiospermum (C. cuchujaquense), la cual pertenece a C. secci6n Carphospermum. Mediante el descubrimiento de esta nueva especie se documenta un patr6n de disyunci6n en la distribuci6n de la secci6n Carphospermum. Cardiospermum L. contains approximately 15 species of herbaceous vines or less often subshrubs. It belongs to the largely neotropical tribe Paullinieae (Sapindaceae) along with five other genera (Serjania Miller, Paullinia L., Urvillea Kunth, Houssayanthus Hunziker, and Lophostigma Radlkofer, Acevedo-Rdgz., 1993: 31). Among these genera Urvillea is the closest to Cardiospermum, since they share numerous synapomorphic characters. In fact, both genera are so closely related that sometimes they are hard to tell apart. However, as a rule, Cardiospermum has inflated capsules that differ from the non-inflated capsules of Urvillea. Cardiospermum occurs throughout the Neotropics, with centers of distribution in west-central Brazil and north-central Mexico. It is the only genus within the Paullinieae with three of its species having a nearly cosmopolitan distribution. The only other member of Paullinieae to occur naturally outside the Western Hemisphere is Paullinia pinnata L., which is also found in tropical Africa (Exell, 1966; Fouilloy & Hall6, 1973). Although Cardiospermum is a relatively small genus, it is perhaps one of the most heterogeneous within the Paullinieae. Cardiospermum is also cytologically diverse, since different chromosome numbers have been reported among the few species analyzed (Ferrucci, 1981). Recent botanical explorations for the ongoing project Flora of the Rio Mayo Region of Sonora have yielded the discovery of a new species of Cardiospermum, which we herein describe. Cardiospermum cuchujaquense M. S. Ferrucci & P. Acevedo-Rodrfguez, sp. nov. TYPE: Mexico. Sonora: El Rancheria, crossing of Rio Cuchujaqui, ca. 22.5 km S of Alamos on road to El Chinal, 26051'N, 108055'W, 200 m, in tropical deciduous forest, 10 Oct. 1992 (fl, fr), T R. Van Devender, R. K. Van Devender, A. C. Sanders & B. Pitzer 92-1178 (holotype, US; isotypes, ARIZ, CTES, MEXU). Figures 1, 2. Suffrutex scandens, subglaber; caule 6-costato, corpore lignoso simplici. Folia stipulis linearibus, 2.5-5 mm longis, acuminatis; folia trifoliolata, foliolis ovatis vel lanceolatis, 3.3-5.8 cm longis, chartaceis, sparsim setulosis, apice longe-acuminatis, margine inciso-dentatis vel lobatis; foliolo terminali basi longe-attenuato, foliolis lateralibus basi cuneatis. Capsula alata, septifraga, chartacea, ambitu trigono-obovato, loculis centraliter inflatis, extus glabris praeter venam dorsalem trichomatibus laxis indutam, intus glabris; seminibus subglobosis, 4.5-5.2 mm diam., trichomatibus paleaceis indutis, arillodio cordiformi. Climbing shrub to 3.5 m long; stems herbaceous, 1-1.5 mm diam., 6-ribbed to nearly terete, pilose, sometimes with scattered minute glandular trichomes; cross section of stem with a single stele. Stipules linen: 2.5-5 mm long, pilose, falcate and usually reflexed, acuminate at apex; leaves trifoliolate; petiole pilose, 1.3-3.7 cm long, furrowed along adaxial surface; leaflets nearly sessile, ovate to lanceolate, often 1-2-lobed, 3.3-5.8 x 1.5-3.3 cm, chartaceous, concolorous, sparsely setulose, especially along veins and abaxial surface, the apex long acuminate, usually glandular, the margins remotely glandular-serrate, the terminal leaflet with a long attenuate base, the base of lateral ones asymmetric with a narrower acroscopic side, cuneate at NovoN 8: 235-238. 1998. This content downloaded from 157.55.39.211 on Fri, 24 Jun 2016 05:43:48 UTC All use subject to http://about.jstor.org/terms