New Species and Combinations in Mexican and Central American Rondeletia (Rubiaceae) David H. LorenceNational Tropical Botanical Garden, P. O. Box 340, Lawai, Kauai, Hawaii 96765, U.S.A. Rondeletia L. (Rubiaceae, Cinchonoideae) in thebroad sense is a tropical American genus comprisingapproximately 125 species of shrubs and small trees(Mabberley, 1987; Willis, 1988) ranging from Mex-ico through Central America into South Americaand the West Indies. While revising the genus forFlora Mesoamericana and Flora of Chiapas, 11new species came to light and are herein describedand illustrated. In addition, two new names are pro-posed. First described by Plumier (1703), Rondeletiawas named for the French physician Gulliaume Ron-delet. The name was later validated by Linnaeus(1753). Rondeletia americana, one of Linnaeus'stwo original species, has been designated as thelectotype species (Hitchcock, 1929: 131.). Plan-chon (1849) subdivided Rondeletia into three gen-era: Rondeletia; Rogiera, segregated from Ron-deletia on the basis of its pentamerous flowers andcorollas with an externally glabrous tube and beard-ed throat with yellow or sometimes white hairs; andArachnothryx, separated on account of its cobweb-by pubescence, tetramerous flowers, and corollaswith a naked throat. Rondeletia thus included onlythose species with pentamerous flowers having afleshy faucial ring (Planchon, 1849). Hooker (1873)and Hemsley (1879, 1881) accepted Rondeletia inthe broad sense, recognizing Arachnothryx and Ro-giera as sections. In his treatment of Rubiaceae for North Amer-ican Flora, Standley (1918) subdivided Rondeletiasens. lat. into 15 species groups, but these namedgroups were given without rank. Four occur inboth Mexico and Central America (Amoenae, Lan-iflorae, Leucophyllae, and Calycosae), two addi-tional ones occur in Central America (Hondurenses,with a single species in Honduras, and Odoratae,which is centered in the West Indies), whereas theremainder are restricted to the West Indies. Stan-dley's Amoenae consists of those species with pen-tamerous flowers having a bearded corolla throatand is thus equivalent to Rogiera. Calycosae, Lan-iflorae, and Leucophyllae have tetramerous flowerswith a naked throat and clearly pertain to the Ar-achnothryx alliance; Standley defined these groupson the basis of pubescence and inflorescence struc-ture. They are poorly differentiated, however, asthe distinguishing characters intergrade, particularlywhen the species included in this paper are consid-ered. Hondurenses is closely related to the latterthree sections, differing primarily in having largepentamerous flowers. Odoratae has pentamerousflowers with a fleshy faucial ring and thus belongsin Rondeletia sens. str. Two species in Odorataehave been recorded from Panama: R. panamensisDC. and R. odorata Jacq. The latter is otherwiseconfined to Cuba but is widely cultivated. Its pres-ence in Panama is likely based on cultivated ma-terial. In view of the available evidence, I believethat Arachnothryx, Rogiera, and Rondeletia (ex-cluding the West Indian species, which I have notcritically studied) are best treated as segregates ofRondeletia, probably at the level of subgenera. Moredetailed discussion is given below. In most modern floristic treatments (e.g., Dwyer,1980; Kirkbride, 1969; Standley & Williams, 1975)Arachnothryx and Rogiera have been consideredas synonyms of Rondeletia. Kirkbride (1969) notedthat capsule dehiscence and seed morphology didnot consistently separate Panamanian Arachno-thryx and Rondeletia species. Arachnothryx wasrecognized at the generic level by Steyermark (1967,1974) in his treatments of Rubiaceae of the GuyanaHighlands and Venezuela. He segregated Arach-nothryx from Rondeletia using a combination ofcharacters involving capsule dehiscence, pubes-cence type, and seed, flower, and stipule morphol-ogy. Unfortunately, Steyermark did not consider inhis study any Rondeletia species (including Arach-nothryx and Rogiera) from Mexico, Central Amer-ica, and the West Indies, areas that are importantcenters of diversity for the group. Borhidi and his collaborators proposed a verynarrow generic concept for Rondeletia, limiting itsscope to include about a hundred West Indian spe-cies (Borhidi, 1982, 1987; Borhidi & FernandezZequeira, 1981, 1982, 1983; Borhidi & Jarai-Kom-l6di, 1983). They consequently resurrected Arach-nothryx and Rogiera and described three new gen-era to accommodate certain species from the West NovoN 1: 135-157. 1991.
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