Two new endemic tree species from Puerto Rico: Pisonia horneae and Pisonia roqueae (Nyctaginaceae).

Marcos A Caraballo-Ortiz,Jorge C Trejo-Torres

doi:10.3897/phytokeys.86.11249

Abstract

In this paper, we describe two endemic tree species of Pisonia (Caryophyllales: Nyctaginaceae) from Puerto Rico that were erroneously catalogued under the single name Pisonia subcordata var. typica f. gigantophylla, misidentified as P. albida or P. subcordata, and informally named as “P. borinquena” and “P. woodburyana”. The species here named as P. horneae is a rare to locally occasional tree from low elevations in the Northern Karst and the Sierra de Cayey. The other species, here named as P. roqueae, is a rare to locally common tree from mid to high elevations in the Central Mountain Range and the Luquillo Mountains. We provide an account of the taxonomical and nomenclatural history of both species, images, conservation notes, a distribution map, and a key to distinguish the species of Pisonia present in Puerto Rico.

Highlights

The Caribbean Islands are considered one of the hottest hotspots of world biodiversity (Myers et al 2000) with a richness that has not been fully documented yet, as evidenced by the dozens of new species described from the region every year (Hedges and Conn 2012, Corgosinho and Schizas 2013, Mercado-Diaz et al 2014, Cardoso and Braga 2015, Aguirre-Santoro et al 2016, Carmenate-Reyes et al 2017)
Our analysis of living and dried specimens shows that the two species of Pisonia recognized by Proctor represent the same two taxa involved in the description of P. subcordata var. typica f. gigantophylla
With the formal addition of P. horneae and P. roqueae, the genus Pisonia in Puerto Rico is represented by six species, including three Puerto Rican endemics, two West Indianrestricted, and one pantropical

Summary

Introduction

The Caribbean Islands are considered one of the hottest hotspots of world biodiversity (Myers et al 2000) with a richness that has not been fully documented yet, as evidenced by the dozens of new species described from the region every year (Hedges and Conn 2012, Corgosinho and Schizas 2013, Mercado-Diaz et al 2014, Cardoso and Braga 2015, Aguirre-Santoro et al 2016, Carmenate-Reyes et al 2017). In 1980 Westra examined and annotated the duplicates of specimen Sintenis 2705 (B, K) and considered them as a mixed collection containing parts of P. albida and P. subcordata Swartz. While the two duplicates of Sintenis 2141 (GH, K) represent the same taxon, at least two of the three duplicates of Sintenis 2705 (B, K, and possibly GH) are mixed and include the same taxon as Sintenis 2141 as well as a second taxon These specimens clearly represent two taxa, their sterile and fragmented nature, as well as the scant protologue, brings uncertainties to assign identities to each of the pieces. Our analysis of living and dried specimens shows that the two species of Pisonia recognized by Proctor represent the same two taxa involved in the description of P. subcordata var.

Materials and methods

Discussion

Notes on reproduction and conservation