Ronabea Aubl. (Rubiaceae: Lasiantheae) Charlotte M. Taylor [webpage] Missouri Botanical Garden P.O. Box 299 St. Louis, MO 63166 USA Ronabea latifolia in French Guiana, courtesy of M.F. Prévost Ronabea Aubl. includes three neotropical species of low shrubs found in wet forests and gallery forests from Belize to Amazonian Brazil. Ronabea has opposite leaves; raphides in its tissues; narrowly triangular, persistent, interpetiolar stipules; shortly cymose to subcapitate, few-flowered, axillary inflorescences with bracts; sessile, small, distylous flowers; white salverform corollas with five valvate lobes; bilocular ovaries with the basal ovules solitary in each locule; rather small, purple-black, drupaceous fruits; 2 unilocular pyrenes that are smooth on the adaxial surface and open by a preformed ventral lid; and oily endosperm (Taylor, 2004). In spite of its small number of species, Ronabea has a rather complicated nomenclatural history as summarized by Taylor (2004). In particular R. latifolia is a rather frequently encountered species with a notable amount of morphological variation, especially in leaf size, shape, and pubescence, degree of expansion of the inflorescences, and corolla size, and it has received several different names. Here this species is circumscribed broadly, pending detailed future studies that will need to include field work. Ronabea has long been considered closely related to or synonymous with Psychotria L. (e.g., Steyermark, 1972), though a few authors have recognized it as a separate genus of Psychotrieae (e.g., Bremekamp 1934). Ronabea species were anomalous in Psychotria in their oily endosperm and also their combination of axillary inflorescences (i.e., borne in both axils at each node), persistent triangular stipules, and blue-black rather than red fruits. One study using molecular systematic data (Piesschaert et al., 2000) found Ronabea to be related to Lasianthus Jack, which has recently been separated in its own tribe based on additional molecular systematic data (Bremer & Manen, 2000). Ronabea has been most recently recognized as a separate genus of Lasiantheae (Taylor, 2004). Key to the Species of Ronabea 1. Stems and leaves, at least adaxially, pilose to hirsute...R. isanae 1. Stems and leaves glabrous to hirtellous or strigillose. 2. Leaves 7-15 x 2-6 cm, drying membranaceous to papyraceous; calyx limb lobed for more than 1/2...R. emetica 2. Leaves 6-20 x 3-10 cm, drying stiffly papyraceous to chartaceous; calyx limb lobed for less than 1/4...R. latifolia References Bremekamp, C.E.B. 1934. Notes on the Rubiaceae of Surinam. Recueil Trav. Bot. Néerl. 31: 248-308. Bremer, B. & J.-F. Manen. 2000. Phylogeny and classification of the subfamily Rubioideae (Rubiaceae). Pl. Syst. Evol. 225: 43-72. Piesschaert F., L. Andersson, S. Jansen, S. Dessein, E. Robbrecht, & E. Smets. 2000. Searching for the taxonomic position of the African genus Colletoecema (Rubiaceae): morphology and anatomy compared to an rps12-intron analysis of the Rubioideae. Canadian J. Bot. 78: 288-304. Steyermark, J.A. 1972. Psychotria. In: B. M. Maguire & Collaborators, Flora of the Guayana Highlands. Mem. New York Bot. Gard. 23: 406-717. Taylor, C.M. 2004. The neotropical genus Ronabea (Rubiaceae, Lasiantheae). Syst. Geogr. Pl. 74: 35-42 TOP List of Names and Synonyms of Ronabea Accepted names are presented in bold; synonymous names appear with an equals sign. Further information on these names can be found in the TROPICOS database [http://www.tropicos.org/]. Appunia parviflora Lundell = Ronabea latifolia Cephaelis emetica (L.f.) Pers. = Ronabea emetica Coffea subsessilis Benth. = Ronabea latifolia Mapouria subsessilis (Benth.) Muell. Arg. = Ronabea latifolia Mapouria subsessilis var. angustifolia Muell. Arg. = Ronabea latifolia Mapouria subsessilis var. genuina Muell. Arg. = Ronabea latifolia Mapouria subsessilis var. latifolia Muell. Arg. = Ronabea latifolia Psychotria axillaris Willd., nom. superfl. = Ronabea latifolia Psychotria emetica L.f. = Ronabea emetica Psychotria erecta (Aubl.) Standl. & Steyerm. = Ronabea latifolia Psychotria erecta f. fluctuans (Standl.) Steyerm. = Ronabea latifolia Psychotria fluctuans Standl. = Ronabea latifolia Psychotria fluctuans var. angustifolia (Muell. Arg.) Standl. = Ronabea latifolia Psychotria fluctuans var. latifolia (Muell. Arg.) Standl. = Ronabea latifolia Psychotria isanae J.H. Kirkbr. = Ronabea isanae Ronabea emetica (L.f.) A. Rich., Nicaragua to western Ecuador, 0-600 m Ronabea erecta Aubl. = Ronabea latifolia Ronabea isanae (J.H. Kirkbr.) C.M. Taylor, Amazonian Brazil, lowlands Ronabea latifolia Aubl., Belize to the Guianas, northern Brazil, and Ecuador, 0-900 m Ronabea latifolia var. hispidula Bremek = Ronabea latifolia Text and Images, unless otherwise indicated, Copyright © by Charlotte M. Taylor. All rights reserved. This webpage was revised on April 8, 2008. TOP