Chiococca insularis (Ridley) C.M. Taylor & M.R. Barbosa, 2015

Jardim, Jomar G., Taylor, Charlotte M., Barbosa, Maria Regina & Pessoa, Maria Do Céo R., 2015, Taxonomic notes on Chiococca and Salzmannia (Rubiaceae, Chiococceae) in northeastern Brazil, with a new combination and a new species, Phytotaxa 202 (1), pp. 15-25 : 18-19

Chiococca insularis (Ridley) C.M. Taylor & M.R. Barbosa , comb. nov.

Palicourea insularis Ridley, J. Linn. Soc., Bot. 27: 41. 1890. Erithalis insularis (Ridley) Zappi & T.S. Nunes, Kew Bull. 55: 655. 2000. TYPE: — BRAZIL. Pernambuco: Ilha Fernando de Noronha , main island, 26 August 1887, Ridley, Lea & Ramage 86 (holotype: BM photo!; isotypes: B destroyed, B as photo F neg. #599 at MO-1695030 and NY, GH web!, K 000016495 web!, K 000016496 web!).

This species is known from a single collection with flowers and fruits from dry vegetation on the island of Fernando de Noronha. The specimen is accompanied by a watercolor illustration of the living plant, and is deposited at BM. This species was described as P. insularis based apparently on its shrub or small tree habit, five-merous corollas with apparently valvate aestivation, and fruits with four pyrenes. However several of its characters do not agree with Palicourea (Palicoureeae) , in particular its apparent lack of raphides, triangular stipules, axillary inflorescences, quincuncial corolla aestivation, and fusiform stigmas that are positioned together with the anthers in open flower; Palicourea is characterized by raphides in the tissues, bilobed stipules, terminal inflorescences, valvate corolla aestivation, and bifid stigmas that are positioned above or below the anthers in the open flowers. Zappi & Nunes (2000) noted that this species also differs from Palicourea in its corollas with the tubes straight at the base and its “four-winged” fruits, although the fruits are better characterized as four-lobed or four-angled with concave sides when dried. Palicourea in its current circumscription ( Taylor et al., 2010) does includes some species with corolla tubes that are straight at the base and fruits with four pyrenes, but Palicourea and its entire tribe are diagnosed by the presence of raphides, bilobed stipules, terminal inflorescences, valvate corollas, and distylous floral morphology, so this species is not correctly classified there.

Zappi & Nunes (2000) transferred Palicourea insularis to Erithalis , based on its funnelform corolla that is deeply lobed, the “four-winged, red fruits”, and probably its shrub or small tree habit, and noted that it apparently has only been collected once. P. insularis also agrees with Erithalis in its lack of raphides, stipule form, axillary inflorescences, anthers that are apparently inserted near the base of the corolla tube, and stigma form and position. The inclusion of this species in Erithalis represented a significant biogeographic expansion for this genus, which is otherwise only known from the Caribbean basin. Zappi and Nunes described the corollas of P. insularis as having the lobes “very reflexed and much longer than the tube”. The corolla lobes are portrayed as moderately reflexed in the watercolor, and are about equal to the corolla tube on the flowers that appear to be just opening on the holotype specimen, to a little longer than the tube on older flowers, apparently due to the tube splitting or shrinking rather than the lobes elongating. The source of Zappi and Nunes’s description of the fruit color is unknown; the collection data for this plant describe only the flower color, the protologue description states that the fruits are green, and the watercolor shows only green fruits. Zappi and Nunes did not describe the corolla aestivation of this species, but in fact the corollas on the holotype are narrowly quincuncial in bud (S. Knapp, pers. comm.). Negrón-Ortiz (2005) accepted the classification of this species in Erithalis and synonimized it with E. fruticosa , which is otherwise known only from the Caribbean basin, and postulated that the plants arrived to Fernando de Noronha by long-distance dispersal from the Caribbean region.

Negrón-Ortiz(2005) also designated a lectotype of P.insularis ,because the holotype at BM was not located.However the holotype specimen was subsequently found, identified and filed as C. alba , thus Negrón-Ortiz’s lectotypification is superseded by the existence of the holotype (ICBN Art. 9.17). In overall aspect and most morphological features, P. insularis agrees with Chiococca as noted by Sandwith in sched. (K) and Bremekamp in sched. (BM): these share the lack of raphides, triangular stipules that are shortly united around the stem, racemiform axillary inflorescences, ovary and calyx form, corolla shape and aestivation, form and position of the anthers and stigmas, and the shape, texture, and form of the fruits. Chiococca is found widely distributed in the continental regions adjacent to Fernando de Noronha, and is also common on tropical islands with dry vegetation (Acevedo-Rodriguez & Strong, 2012; Robinson, 1902; Steyermark, 1974). Chiococca and Erithalis are distinguished only by ovary and fruit characters, and have different biogeographic distributions. Erithalis has ovaries with five to twenty ovules and subglobose to oblate fruits that are purple to pink at maturity and have five to twenty pyrenes ( Negrón-Ortiz, 2005). Apart from E. insularis this genus is found only in the Caribbean basin and Venezuelan coast, with the closest populations to Fernando de Noronha in Trinidad and on several of the islands west of there and off the coast of Venezuela ( Steyermark, 1974), a marked disjunction. Chiococca , as noted above, is widespread in the tropical and warm temperate Americas, and has white or yellowish white corollas and generally ellipsoid mature fruits. Chiococca is generally described as comprising vining species, but the genus includes several species that are shrubs or small trees ( Lorence, 2012; Delprete, 2010). Chiococca is also generally described as having ovaries with two locules and ovules and fruits with two pyrenes, but actually the number of locules and pyrenes varies. Müller (1881) described the ovaries of Chiococca as two- or less often three-locular, and the fruits of some specimens of Chiococca alba have been reported as variously bi- and trilocular on the same individual plant in the Galapagos Islands ( Robinson, 1902). Zappi and Nunes (2000) described the fruits of E. insularis as four-locular although the protologue described them as five-locular, and the holotype specimen has fruits that appear to have variously two, three, four, and five developed pyrenes in ellipsoid fruits on the same plant. This ovary arrangement seems to differ significantly from that of Erithalis , which consistently has five or more pyrenes in the plurilocular species. Based on these characters and the biogeographic ranges of the two genera, P. insularis is here transferred to Chiococca . The inclusion of this species expands the characters of Chiococca to include ovaries with up to five locules.