Ipomoea electrina (Convolvulaceae): A New Name for Exogonium luteum House Daniel F: AustinArizona-Sonora Desert Museum, 2021 N. Kinney Road, Tucson, Arizona 85743, U.S.A. J. Andrew McDonald Department of Botany, University of Texas, Austin, Texas 78713, U.S.A.AnriTACT'. The history of a southern Mexican en-demic Ipomoea is summarized, beginning with itspuIllication in 1908 as Exogonium luteum House.Because of a previously existing Ipomoea luteaHlemsley. the new name Ipomoea electrina is pro-posed to refer to the unique amber-colored flowersof these plants. Since two distantly related conge-ners, Ipomoea lutea and /. urbinei, have nomencla-tural and misidentification histories interlaced wiitI. electrina, they are also discussed and comlarediwith this taxon.IKist MEN. Se presenta on resumen de la historiade una Ipomoea endleica del sur de Mexico, em-pezando con su publicaci6n en 1908 como Exo-gonium luteum House. Iebido a la previa existen-cia de una Ipomoea lutea Hemlsley. se propone elnuevo nombre Ipomoea electrina en referencia alcaracterfstico color ambar que poseen las flores deestas plantas. Dos congeneres lejanamente rela-cionalos, Ipomoea lutea e Ipomoea urbinei, con his-torias de nomenclatura y err6neas identificacionesentrelazadas con Iponmoe electrina. tamlbidn se dis-cuten v comparan con este tax6n. Key words: biodiversity, convergence. Convol-vulaceae. Exogoniumn, Ipomoe(, Mesoamerica,morning glories. New Worll. Homer 1). House described numerous NewWorld Convolvulaceae (House, 1905, 1906a-d,1907a-e. 1908a-d. 1909). among them Exogoniiumlute'um. a name and species that has proven con-troversial in recent years (Austin, 1978. 1983: Mc-Pherson. 1979). House (1908d) originally put thespecies in Exogonium, a genus that he consideredto be distinct and closely related to Ipomoea, butdistinguishable on the basis of its exserted stamensand style (i.e., exo-goniu). New World morning glo-ries of this type, usually presenting yellow, orange,or red, salverform corollas, are generally associatedwith bird pollination. or the occasional visitationsof butterflies (Austin, 1978, 1997: McDonald,1987. 1991). Subsequent authors have recognizedthat this ornithophilous syndrome has arisen on nu-merous occasions within New World Convolvula-ceae, especially within the genus Ipomoea s.l., in-cluding most of the original elements that Houseassigned to Exogonium. Consequently. modern stu-dents of the family have considered the exogonioidtaxa largely as derivative species that should beaccommodated in various sections within Ipomoea(Austin, 1997: Mcl)onald 1987, 1991: McPherson.1979). Some species of Exogonium sensu Housewere retained in Ipomoea sect. Exogonium (Choisv)Grisebach (McDonabl. 1987), while others weretransferred to Ipomoea sect. Mina (Cervantes) Cri-sebach (Austin, 1978. 1980) and Ipomoea sect. Er-iospermum Hallier f. (Austin, 1980). and yet othersto Turbina (Austin & Staples. 1991). and evenRuellia (Austin & Wasshausen. 1973) of the Acan-thaceae. Exogonium liuteum requires the same con-sideration, though its legitimate transfer to Ipomoeahas yet to take place.I'AXONOMIC PROBLtI-M Austin (1978) maintained Exogonium luteum inIpomoea, but noted that the specific epithet of thebasionym could not be applied to the genus due tothe priority of Ipomoea lutea Hemsley. Austintherefore proposed a new name for the species, 1.shinnersii, under which was also recognized Ipo-moea shinnersii var. woronovii (Standley) I). F. Aus-tin (1978). Unfortunately. the epithet uoronorii infact has priority over the epithet shinnersii due toits earlier publication (late, and therefore rendersI. shinnersii as an incorrect name under Article52.3 of the Code ((,renter et al, 2000). Later. Austin(1983) corrected that mistake by creating I. woron-ovii (Standley) 1). F. Austin. while still interpretingE. luteum as a synonym of I. woronorii. McPherson (1979) also realized the misinterpre-tation, and proposed Ipomoea crocea as a new namefor Exogoniurn luteumn n his dissertation. Unhap-NovoN 12: 27-30. 2002.
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