Pisonia roqueae Trejo & Caraballo, 2017

Caraballo-Ortiz, Marcos A. & Trejo-Torres, Jorge C., 2017, Two new endemic tree species from Puerto Rico: Pisonia horneae and Pisonia roqueae (Nyctaginaceae), PhytoKeys 86, pp. 97-115 : 100-105

Pisonia roqueae Trejo & Caraballo sp. nov. Figs 3 , 4 , 5 , 6

Pisonia subcordata sensu Heimerl and Urban (1905), not Swartz (1788).

Pisonia subcordata Swartz var. typica Heimerl f. gigantophylla Heimerl. Bot. Jahrb. Syst. 21: 630. 1896. Pro parte (see Additional specimens examined section). Lectotype (designated here): Barranquitas: Prope Barranquitas in sylva primaera montis Torrecilla, 30 Oct 1885, Sintenis 2141 (GH [00037444]; K [H2005/00995]).

" Pisonia borinquena Proctor", nomen nudum.

Type.

PUERTO RICO. Municipio de San Germán, Bo. Caín Alto, Maricao State Forest, in a moist ravine, south of Road 120 km 15.6, 850 m, 23 June 1992, G.R. Proctor, R. Padrón, and R. Rivera 48064 (holotype: US! [#00707324]; isotype: MO! [#04580139]).

Diagnosis.

Pisonia roqueae is distinguished from congeners from Puerto Rico by a combination of the following characters: staminate inflorescences with globose crowns, twigs glabrescent, leaves coriaceous and glabrescent, and fruits clavate and reddish-black with five rows of viscid glands on their distal half.

Description.

Trees dioecious up to 25 m high with trunks up to 1 m in diameter. Bark finely and vertically striated, grayish with lenticels about 3 mm in diameter. Twigs ancipitous, ferruginous-brownish, and pubescent when young; terete, glabrescent, and grayish when old. Leaves clustered towards the ends of branches, opposite, subopposite, or sub-verticillate, decussate; petioles up to 3.5 cm long, yellowish green; blades elliptic, obovate, or roundish, 10-17 (-25) cm × 7-12 (-16) cm, apex acute to rounded, sometimes cuspidate, base acute to cuneate, margin entire or slightly wavy, adaxial and abaxial sides glabrous, coriaceous, drying coriaceous, dark green above, slightly paler below; veins pinnate, reticulate, up to eleven pairs, opposite or alternate, blackish. Inflorescences terminal or axillary, dendroid, to 7 cm long; crowns compact; staminate inflorescences with a globose crown; pistillate inflorescences with a flabellate crown. Flowers fragrant; pistillate flowers with perianth cylindrical-campanulate-oblong at anthesis, 2 mm long, puberulent; staminate flowers perianth campanulate at anthesis, green, about 3 mm long, puberulent. Infructescences dendroid, 4-7 cm long, drying reddish or brownish; peduncle angled, 2-3 cm long; branches irregularly forked, with minute bracteoles around the base of anthocarps. Fruits anthocarps (achenes), clavate, 10-15 mm x 2 mm, longitudinally striate, tip cuspidate; husk glabrous, with five lines of glands over discrete ribs along the distal third or half; glands capitate, about 0.5 mm long, viscid.

Habitat and ecology.

Pisonia roqueae is mainly distributed from middle to high elevations. In the Central Mountain Range and Sierra de Luquillo, the species have been found on wet and moist serpentine or volcanic forests from 480 to 950 m. The only known locality from the Northern Karst is on a wet limestone forest at ca. 330 m.

Unlike other species of Pisonia from Puerto Rico, adult trees of P. roqueae can reach considerable heights (> 15 m). Some large trees can be found at the Maricao State Forest and at the Luquillo Mountains in EL Verde Field Station, including the Luquillo Forest Dynamics Plot (http://luq.lternet.edu), where the species (treated as either " P. borinquena " or P. subcordata ) has been included in long-term studies (e.g., Kress et al. 2010).

Some species of Pisonia from Puerto Rico, including P. roqueae , are common hosts for native species of mistletoes. For example, P. albida and P. roqueae are important hosts for Phoradendron anceps (Spreng.) M. Gómez ( Santalaceae ) at the Guánica State Forest and the Maricao State Forest, respectively ( Pinto 2005). Similarly, P. subcordata has been reported as host for the mistletoes Dendropemon caribaeus Krug & Urb. ( Loranthaceae ) and P. anceps in northern Puerto Rico (M.A. Vives-Heyliger, pers. comm.).

Phenology.

Pisonia roqueae has been recorded flowering in April, June, and July, and fruiting from January to April.

Vernacular names.

As with other tree species of Pisonia from Puerto Rico, P. roqueae is locally known as corcho or corcho blanco.

Etymology.

It is our honor to name Pisonia roqueae after Dr. Ana Cristina Roqué Geigel de Duprey (1853-1933), an amateur ethnobotanist from Puerto Rico who dedicated over three decades of her life to prepare the bilingual manuscript " Botánica Antillana: Introduction to the study of the picturesque flora of Porto Rico and West Indies ", aimed to make botany accessible to the general public. Her manuscript ( Roqué de Duprey 1925) was never published and remained in oblivion to the botanical community until recently when JCTT and collaborators divulged its existence ( Martínez 2015). Roqué de Duprey is mostly known for being an educator, writer, suffragist, and one of the founders of the University of Puerto Rico-Mayagüez, among other educational institutions.

Abundance and conservation.

Pisonia roqueae has been observed as a locally common tree in two localities in the eastern and western Central Mountain Range (Monte La Torrecilla in Barranquitas and Maricao State Forest, respectively), occasional at the El Yunque National Forest (Luquillo Mountains), and rare elsewhere. It has been also recorded from Cayey (including an unvouchered locality at Bo. Jájome, 300-350 m, 18 Feb 2015, by O. Monzón), Guayama at Sierra de Cayey, and a single record from the Northern Karst at Sabana Hoyos, Arecibo. The species is preliminary considered as “Imperiled” (sensu NatureServe) or “Vulnerable” (sensu IUCN Red List) by Gann et al. (2015-2017).

Additional specimens examined.

PUERTO RICO. Arecibo: Bo. Sabana Hoyos, Finca Las Abras, 330 m, 9 Sept 2002, Trejo 1773 (UPRRP); 300 m, 10 Jul 2005, Trejo 2996 (UPR) ; Barranquitas: Bo. Barrancas, Monte La Torrecilla , 900-1100 m, 19-20 Mar 1915, Britton et al. 5628 (NY); 950 m, 1 Apr 1989, Proctor 45465 (FTG, UPR); 930 m, 24 Jul 2003, Trejo 2340 (FLAS, GH, UPR); Trejo 2342 (NY, UPR); Trejo 2343 (UPR); 5 Mar 2004, Trejo 2552 (UPR); Trejo 2553 (UPR) ; Cayey: Cercadillo, 600 m, 10 Feb 1983, Liogier 33875 (UPR) ; Ciales: Bo. Toro Negro, Tres Picachos, 700 m, 29 Jul 1993, Axelrod 6694 (JBSD, UPRRP); Bo. Cialitos, Los Tres Picachos, 675 m, 4 Apr 2008, Caraballo et al. 2561 (UPR) ; Guayama: Bo. Carmen, 290 m, 4 Jun 2016, Areces et al. 1140 (UPRRP) ; Maricao: Maricao Forest, 800 m, 26 Jun 1938, Sargent 506 (MO); 500 m, 2 Oct 1938, Sargent 633 (MO); Vivero de Peces, 850 m, 13 Jul 1950, Little 13380 (F, NY, UPR); 880 m, 15 Jul 1950, Little 13404 (F, NY, UPR); 26 Nov-4 Dec 1963, Duke 7134 (MO); Monte Alegrillo, 890-900 m, 5 Apr 1987, Proctor 43322 (US); Monte del Estado , 700 m, 6 May 1990, Caminero 282 (MAPR); Bo. Maricao Afuera, Monte del Estado , 850 m, 15 May 1991, Caminero 443 (MAPR); 480 m, 3 Apr 1996, Cedeño 881 (MAPR); 550 m, 4 Apr 1996, Cedeño 904 (MAPR); 840 m, 29 Feb 2004, Carlo 21 (UPR); 875 m, 27 May 2009, Caraballo et al. 2878 (UPR); s.c. s.n. (MAPR [016698]) ; Sabana Grande: Bo. Sabana-Tabonuco, 750 m, 5 Mar 2004, Trejo 2648 (UPR) ; San Germán: Bo. Caín Alto, Maricao Forest, 810-830 m, 23 Jan 1988, Proctor 44432 (US) ; San Lorenzo: Prope Hato Grande in sylva primaera montis Gregorio, 31 Aug 1885, Sintenis 2705 [mixed specimens, see Introduction and Additional specimens examined for P. horneae ] (B [10-0217019]; GH [00037445]; K [K000036122]) ; Río Grande: El Verde Experimental Station, 29 Jun 1963, Smith 345 (EVFS [El Verde Field Station herbarium]); August 1963, Smith 470 (EVFS); 15 May 1964, Smith 1122 (EVFS); LTER plot, 350 m, 18 Jun 1990, Moestl 9 (EVFS); 419 m, 2 Mar 2013, Areces 748 (UPRRP); Rio Sonadora , 350 m, 18 Jun 1991, Taylor 10453 (MO); 19 May 1994, Taylor 11689 (MO) ; Utuado: without locality, 1916, Strube s.n. “A” (MO [#653326]); Bo. Roncador, Hacienda Verde, 514 m, 8 Aug 2004, Trejo 2731 (UPR); Without locality: without date, 8 Nov 1886, Sintenis 4355 [see Introduction and Additional specimens examined for P. horneae ] (B, n.v., probably lost) .

Figures

Figure 3. 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).

Figure 4. 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.

Figure 5. 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.

Figure 6. 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.