Merger of the Endemic Hawaiian Genera Cyanea and Rollandia (Campanulaceae: Lobelioideae) Th omas G. hammers Department of Botany, Field Museum of Natural History, Chicago, Illinois 60605-2496, U.S.A. Thomas J. Givnish and Kenneth J . Sytsma Department of Botany, University of Wisconsin, Madison, Wisconsin 53706-1381, U.S.A. ABSTRACT. Phylogenetic analyses based on mo¬ lecular data indicate that the species of Rollandia are embedded within the genus Cyanea and that together these genera forma inonophyletic group. CyaneaandRollandiaarethereforemergedunder the former name. A revised key to the baccate generaof HawaiianFobelioideaeandanexpanded description of the genus are provided; eight new' combinations and one new name are proposed; and lectotypes are selected for Rollandia humboldtiana and R. longi flora var. angustifolia. This expanded circumscription makes Cyanea the largest genus in the Hawaiian flora, with 64 species and 10 heter- onymic subspecies. The flora of the Hawaiian Islands includes 114 endemic species of woody Lobelioideae (Campanu¬ laceae),95ofwhichhavebaccatefruits(hammers, 1990, 1992a; Lammers & Lorence, 1993). Tra¬ ditionally(Gaudichaud,1826;Bentham&Hooker, 1876; Hillebrand, 1888; Schonland, 1889; Hock, 1919; Wimmer, 1943), these baccate species have been divided among four genera: Clermontia Gau¬ dichaud, Cyanea Gaudichaud, Delissea Gaudi¬ chaud,andRollandiaGaudichaud.However,var¬ ious alternative classifications have been proposed. Presl (1836) and de Candolle (1839) recognized a fifth genus, Macrochilus C. Presl. Gray (1861), however,recognizedonlythree;Macrochiluswas included in Cyanea and the species of Rollandia were divided between Cyanea and Delissea. En- dlicher (1836) and Dietrich (1839), taking a very broadviewof genericcircumscription, assignedall Hawaiian lobelioids to cosmopolitan Lobelia L. Bail- Ion (1885), on the other hand, treated the baccate Hawaiian species as a single genus, Delissea, with thefourtraditionalgeneraassections.Theclassi¬ fication of von Post and Kuntze (1903) was similar, except Rollandia was maintained as distinct. St. John (1987) merged Cyanea and Delissea under the latter name, but maintained Clermontia and Rollandia as distinct genera. The traditional four- genus classification was employed in the most recent taxonomic summary of theHawaiianCampanula¬ ceae (Lammers, 1990). Recent phylogenetic analyses based on restriction site variation in the chloroplast DNA of Hawaiian lobelioids (Givnish et al., in press) have shown that the species comprising Rollandia are embedded withinCyaneaastraditionallycircumscribed,that CyaneawithoutRollandiaisparaphyletic,andthat the two genera together form a monophyletic group. Specifically, Rollandia is part of a major clade that is defined by 10 synapomorphic mutations and gen¬ erally characterized by orange fruits and an un¬ branchedhabit.Withinthismajorclade,Rollandia formsanunresolvedcladedefinedbythreemuta¬ tions. Morphologically, the two genera are very similar. Every author for over 100 years has distinguished Rollandia solely on the basis of a single feature, i.e., the adnation of the stamina! column to the corolla (Hillebrand, 1888; Schonland, 1889; von Post & Kuntze, 1903; Hock, 1919; Wimmer, 1943; Lammers, 1990). The traditional classification of Campanulaceae includes several such cases of close¬ ly related genera distinguished by a single morpho¬ logical feature, e.g., CampanumoeaBlumeandCo- donopsisWallich,LobeliaandPratiaGaudichaud. The circumscription of such genera must be revised if a natural classification of the family is ever to be achieved(Lammers,1992b,c). Inordertoprovideamorenaturalclassification of the baccate Hawaiian lobelioids, Cyanea and Rol¬ landia are here merged. Although Gray (1861) transferred some species of Rollandia to Cyanea . the species that was later designated as the lectotype of the genus (R. lanceolata) was assigned to De¬ lissea.Becausenopreviousauthorhaseffectively merged just Cyanea and Rollandia , and because thetwogenericnamesareof equal priority, wehave the prerogative of choosing the name to be retained. Novon 3: 437-441. 1993.