Taxonomic novelties in Orthaea (Ericaceae: Vaccinieae)

Several taxonomical novelties of the genus Orthaea (Ericaceae: Vaccinieae) are presented. Two new species, O. eteocles and O. fissiflora , are described and illustrated, the limits of O. glandulifera are redefined to include O. oedipus as a synonym, and the status of a poorly known species, O. ignea , is also discussed.


INTRODUCTION
The plant family Ericaceae, with more than 4100 species, is an important floristic element of tropical montane ecosystems (Stevens et al. 2004). In the northern Andes, this family is represented by more than 600 species, most of them restricted to mid-elevation rain forests (Luteyn 2002). Orthaea Klotzsch, which includes 37 currently accepted species (Salinas 2015), is one of the least studied genera of neotropical Ericaceae. Traditionally, this genus has been delimited by the presence of conspicuously dimorphic stamens with filaments of alternating lengths and equal-sized anthers . Although most species of Orthaea are found in Andean forests from Colombia to Bolivia, some are found in the Guiana Shield (Venezuela and Guyana) and Central America (S Mexico-Panama).
Phylogenetic affinities of Orthaea have remained largely elusive. Phylogenetic analyses have established that the genusas traditionally circumscribed-is paraphyletic (Kron et al. 2002, Pedraza-Peñalosa et al. 2015, Salinas 2015. Species from the Guiana Shield-along with O. stipitata (Luteyn) Luteyn (Mexico)-belong to a clade of extra-neotropical origin that includes some Vaccinieae from Southeast Asia, such as Paphia Seem. and Dimorphanthera J.J. Sm. Although all Andean species belong to the Neotropical clade (sensu Kron et al. 2002), there are multiples lineages within. With the exception of Orthaea madidiensis Pedraza & Luteyn, that has been recovered within a clade of Bolivian species of Thibaudia J. St.-Hil. and Satyria Klotzsch, the remaining species of the genus belong to a clade of heterandrous (highly anisomorphic stamens) taxa that contains most of the diversity of Cavendishia Lindl., Satyria, and Andean Orthaea. Although most of the species of Orthaea belong to the latter clade, relations within such lineage are poorly supported (Pedraza-Peñalosa et al. 2015, Salinas 2015. Therefore, such studies do not recommend a re-circumscription of Orthaea until more robust and copiously sampled phylogenies were procured. As a result of a recent detailed taxonomic and phylogenetic study on Orthaea (Salinas 2015), several taxonomic novelties were discovered, including two new species, the re-circumscription of a poorly known species, and a new synonym, all of which are here presented.

Distribution and ecology.
Orthaea fissiflora is restricted to La Paz department, Bolivia, in humid montane forests at 2100-3400 m. Flowering in March-May. Fruiting in January, March, April, May, July, September, and November.
Etymology. The specific epithet makes reference to the senescence of the corolla after anthesis, tearing along a longitudinal slit.
Orthaea fissiflora is characterized by its small leaves (up to 6.6 × 2 cm), short inflorescence axis (up to 20 mm long), and small green corollas (14-18 mm long) that very often tear apart longitudinally after anthesis, exposing the style and stamens. Morphologically, the closest species is O. pinnatinervia, from which it differs by the characters mentioned in the diagnosis.