Priogymnanthus colombianus (Oleaceae), a new species and first record of genus to Colombia

Priogymnanthus colombianus , a new species and the first record of the South American genus of Oleaceae for Colombia is described and illustrated also we present a dichotomic key for the known species of genus. The new species differs from the three knowns for Priogymnanthus by: leaves oblong or oblong-elliptic, completely glabrous, petioles 10–17 (19) mm; inflorescences 15–20 (25) mm in length, with glabrous rachis, anthers about 3 mm length; fruits (10) 12–15 mm in diameter. P. colombianus occurs on premontane and dry forest in Colombia between 719 and 1213 m of elevation. Based on general threats to its ecosystems and few records found, we black-bluish dry rounded shorter petals (2 mm), longer anthers (3–4 mm) and longer fruits (20–25 mm). P. saxicolus Lombardi diverge by smaller elliptic leaves (4–9 cm), shorter petioles (6–9 mm) and persistent villose indumentum on abaxial blades and inflorescences of smaller size (7 × 7 mm) with sessile anthers and thicker pistil.


Introduction
Historically, Oleaceae (Lamiales) were only represented in Colombia by two native species of the Pantropical genus Chionanthus Linnaeus (1753: 8). In recent years, new records for two cultivated species and descriptions of three new species in 2016, increased this number to seven, all in the same genus (Bernal 2015, Fernández-Alonso & Cogollo 2016, Fernández-Alonso & Cogollo 2017. The new species of Priogymnanthus P.S. Green (1994: 280) Wallander & Albert (2001: 390)) described here, adds a second Oleaceae genus to the Colombian flora and a fourth member to this genus. The genus Priogymnanthus formerly included the two species: P. apertus (Ståhl 1991: 54) P.S. Green endemic to Ecuador and P. hasslerianus (Chodat in Chodat & Hassler 1903: 914) P.S.Green from Bolivia, Brazil and Paraguay. Later, P. saxicolus Lombardi (2015: 66) was described from Brazil.
Recent molecular studies place Priogymnanthus together with Forestiera Poiret (1812: 664) and Hesperelaea A. Gray (1876: 83) in an isolate monophyletic lineage with strong to moderate support (Wallander & Albert 2000, Zedane et al. 2016. Priogymnanthus is distinguished from its close relative Forestiera by the presence of corollas and hermaphrodite flowers, which are very rare in the latter genus (Lombardi 2015). From Hesperelaea, an extinct genera Guadalupe Island (Mexico) endemic, differs by smaller flowers (ca. 5 mm) with linear-lanceolate petals without calyx versus longer flowers (ca. 10 mm) with clawed petals and calyx presence. It is further distinguished from Chionanthus by the absence of calycine verticil, the presence of early deciduous corollas, and the androecium always consisting of four stamens. Although flowers with four stamens are also present in some species of Chionanthus and Hesperelaea members of Oleaceae are typically recognized by flowers with two stamens (Sher & Weber 2009).
The new species presented here was first collected almost 40 years ago in Tolima (Magdalena Valley) Colombia by Raúl Echeverry. The specimen had only immature inflorescences and remained indetermined until we could find two other flowering records from Antioquia. Using flower and fruit samples from trees of one of these localities fixed in 70% ethanol, we were able to confirm that it clearly represents a new species of Priogymnanthus and thus also the first record of the genus for Colombia.

Materials and methods
For the present study, we followed classic taxonomic morphological methods. We described color of vegetative and reproductive parts, and indumentum from both live plants and herbaria specimens. We did measurements of reproductive organs from material conserved in ethanol, but some herbarium material like young inflorescence and flowers were rehydrated and dissected. We use a stereoscopic microscope Nikon SMZ645 to dissect, and measure flowers and fruits. In addition, detailed photographs were taken using a Canon Power Shot A70 camera. Physical specimens were studied from HUA and COL (acronyms according to Thiers B. 2016), additional material was consulted as digital images in Tropicos (2018) and JSTOR (2018). To assess the conservation status for the new species, we followed IUCN criteria and subcriteria that are based on geographical information (Criteria B), because there is no information about population size or population size trends. (IUCN 2017). We used the R package "ConR" to estimate the following Red List parameters: Extent of occurrence (EOO), number of subpopulations, number of locations, and proportion of occurrences within protected areas (Dauby 2018) (R Core Team 2018). For these analysis in ConR, we used the shape file of protected areas in Colombia available at The World Database on Protected Areas (Protected Planet 2019). ConR provides the output distribution map. It resembles Priogymnanthus apertus (B. Sthal) P.S. Green by leaves oblong-elliptic and glabrous, but differs in longer petioles (10-19 mm vs. 5-10 mm), longer inflorescences ((15)18-25 mm vs. 15-19 mm), petals linear-lanceolate of 4-5 mm long vs. petals narrowly elliptic, 2 mm long, shorter anthers (3 mm vs 3-4 mm), and smaller globose fruits (10-15 × 11-14 mm vs. obpyriform fruits, 20-25 × 17-20 mm).
Etymology:-The specific epithet refers to the country of origin for the known collections of this species. Vernacular name and uses:-Cerezo. Timber species and feeding for animals like squirrels. Phenology:-According to Priogymnanthus colombianus specimens and phenological record, this species is flowering from April to October and fruiting from November to February. After flower pollination ripening of fruits takes at least two months Distribution and habitat:-Priogymnanthus colombianus is distributed in Colombia with only three records from the departments Antioquia and Tolima. It occurs in in the Cauca Valley between the western slope of Cordillera Central and the eastern slope of Cordillera Occidental, as well as areas close to Magdalena Valley on the western slope of Cordillera Oriental in the Colombian Andes ( Figure 4). It seems to thrive in the transitional zone from premontane forests to dry forest, at elevations between 719-1213 m. The Antioquia population grows on very steep and rocky soil on the humid banks of a creek.