Pisonia horneae. A Branch showing adaxial side of leaves B Abaxial side of leaves C Staminate (left) and pistilate (right) flowers at anthesis D Seedlings E Bark F Lower trunk of an adult tree. Note the characteristic swollen base observed in all Pisonia from Puerto Rico, where the trunk base wraps over the rocks as it grows. Photo credits: A–B, E–F: JCTT; C–D: MACO.

Isotype specimen of Pisonia horneae from the University of Florida Herbarium (Trejo et al. 2310, FLAS [230768]). Photo courtesy of The University of Florida Herbarium (FLAS) – Florida Museum of Natural History.

Distribution of Pisonia (excluding P. aculeata) in Puerto Rico and adjacent islands based on herbarium specimens. Empty symbols represent historical localities where populations have been presumably extirpated (see Trejo-Torres 2005 and this study for details).

Fruits of the six species of Pisonia from Puerto Rico. A P. aculeata B P. albida C P. horneae D P. roqueae E P. subcordata F P. taina. Reference specimens: A Rose 3548, US B Little 13219, US C Acevedo-Rdgz. 13404, US D Proctor 44432, US E Breckon 7766, US; and F Trejo 2371, US.

Pisonia roqueae. A Foliage B Adaxial side of mature leaves C Twig with ferrugineous-brownish pubescence, turning grayish as it ages D Pistillate inflorescence and young leaves E Ripe infructescence F Trunk of an adult tree. Photo credits: A–C, F: Fabiola Areces (Areces Berazain et al. 2013-2017); D–E: JCTT.

Holotype specimen of Pisonia roqueae from the National Herbarium of the Smithsonian Institution (Proctor et al. 48064, US [00707324]). Note the dendroid staminate inflorescences with globose crowns and the leafless branches during the flowering period. Photo courtesy of The United States National Herbarium, Smithsonian Institution.