Introduction

Picrasma Blume (Simaroubaceae) was described based on P. javanica Blume from the island of Java (Blume 1825). The genus comprises nine species, two of them from Asia and the remainder from the neotropics; eight species were reported by Clayton (2011) and one was recently described by Palacios (2015) from Ecuador. The species of Picrasma are androdioecious trees or shrubs with imparipinnate leaves with entire or serrate margins, axillary or terminal inflorescences, 4- or 5-merous flowers, alternipetalous stamens, an apocarpic ovary with a fleshy intrastaminal disk, and a fruit composed of 1–3(–5) free, drupaceous, globose mericarps.

For the Cuban archipelago, three species of Picrasma have been reported: P. cubensis Radlk. & Urb. and P. excelsa (Sw.) Planch. grow in W Cuba, whereas P. tetramera (Urb.) W. W. Thomas & al. is endemic to C Cuba (Thomas & al. 2011).

In October of 1978, during an expedition organized by National Botanical Garden of Cuba, Johannes Bisse and a group of Cuban and Hungarian botanists found sterile plants, which were collected and later preserved at HAJB under the number A. Álvarez & al. HFC 38198, without any identification. As part of the studies that are being carried out for the revision of Simaroubaceae in Cuba, the collections of HAJB were critically studied and the above-mentioned specimen was found and identified as Picrasma. Further comparison with specimens of the three other species of Picrasma occurring in Cuba suggested that it could represent an undescribed species. The lack of flowers and fruits, however, frustrated the description of the new species until botanists of the province of Holguín, in May of 2017, discovered a population of Picrasma, with flowers and fruits, presumably the same population found by Johannes Bisse and collaborators 39 years earlier. As previously suspected, characteristics of the leaves and inflorescences of the plants collected at Loma El Templo in Holguín province differ from the other Cuban Picrasma, and it is described here as a new species.

Fig. 1.

Holotype of Picrasma pauciflora, González & al., UCLV#12355 (ULV). – Photograph by Arnaldo Toledo.

Fig. 2.

Picrasma pauciflora – A: leaf showing number of leaflets and their abaxial surface; B: bisexual flower with tiny, immature fruits; C: drupaceous mericarps; D: drupaceous mericarp in lateral view, showing gynophore developed from intrastaminal disk. – All photographs taken at: Cuba, Holguín, Rafael Freyre, Loma El Templo, 23 May 2017; A, B: by José Luis Gómez-Hechavarría; C, D: by Pedro A. González-Gutiérrez.

Picrasma pauciflora A. Noa & P. A. González, sp. nov. – Fig. 1, 2.

Holotype: Cuba, province of Holguín, municipality of Rafael Freyre, Loma El Templo, al oeste de la Bahía Naranjo, 70–80 m, bosque semideciduo microfolio, 23 May 2017, P. A. González, W. Carmenate, J. L. Gómez & W. Bonet, UCLV#12355 (ULV! [Fig. 1]; isotypes: B!, HAC!, HAJB!, PAL-Gr!, ULV!).

Morphological diagnosis — Picrasma pauciflora is similar to P. cubensis and P. tetramera by having dentate leaflets with prominent veins, but it differs from them by being a small tree and by having smaller leaves (3–4 cm long), fewer leaflets (3–5) per leaf, and fewer flowers (2–4) per inflorescence. Table 1 shows characteristics that distinguish all four species of Picrasma distributed in Cuba.

Morphological description — Trees small, androdioecious, 4–5 m tall. Leaves 3–4(–6) cm long (Fig. 2A); petiole 7–10(–14) mm long; leaflets 3–5, elliptic or less commonly obovate; lateral leaflets opposite or subopposite, subsessile, 1–1.5 × 0.5–0.7 cm, base cuneate, margin dentate (with 6–14 pairs of small teeth), slightly revolute, apex acute; terminal leaflet 1.8–2.5(–3.5) × 0.5–1(–1.5) cm; venation pinnate, reticulate abaxially, midvein and secondary veins conspicuous on both surfaces, prominent abaxially, secondary veins in 6–14 pairs, scattered hairs present on midvein and secondary veins on both surfaces, but more abundant on midvein abaxially, glabrescent. Inflorescence a 2–4-flowered cyme; pedicels 2.5–3 mm long, pubescent. Flowers bisexual or staminate; bisexual flowers 4- or 5-merous, c. 3 mm in diam.; sepals green with apex reddish, obovate-spatulate, ≤ 1.2 mm long, densely pubescent abaxially, margin dentate; petals green, ± obovate-spatulate, 1.8–2 × c. 1.2 mm in widest part, glabrous; stamens as many as petals (4 or 5); filaments inserted on intrastaminal disk, c. 1.2 mm long, glabrous; anthers dorsifixed, yellow, c. 0.4 × 0.3 mm; ovary apocarpic (Fig. 2B); style fused; stigmas free. Staminate flowers not seen. Fruits 1–3(–5) free, drupaceous mericarps, each mericarp turning red when ripe (Fig. 2C), globose, c. 6 mm in diam., with gynophore developed from intrastaminal disk (Fig. 2D), calyx persistent. Seeds c. 4 mm in diam.

Fig. 3.

Map showing distribution of Picrasma pauciflora (•) at Loma El Templo in Holguín province, Cuba.

Table 1.

Comparison of the species of Picrasma distributed in Cuba.

Phenology — The species has been collected in flower and fruit in May.

Distribution and ecology — Picrasma pauciflora is a strict endemic of the coastal fringe of the province of Holguín in NE Cuba. It has been collected only at Loma El Templo west of Bahía Naranjo, in the municipality of Rafael Freyre (Fig. 3). It grows in microphyllous, semi-deciduous forest (Capote & Berazaín 1984) with other trees species including: Ateleia sp., Bursera simaruba (L.) Sarg., Coccoloba diversifolia Jacq., Guapira obtu-sata (Jacq.) Little, Hyperbaena cubensis (Griseb.) Urb. and Ziziphus bullata (Urb.) Borhidi. In the understory of this forest the shrub species include: Malpighia lineari-folia F. K. Mey., Ravenia spectabilis subsp. leonis (Vict.) Beurton and Trichilia pungens Urb. The vines Mascagnia lucida W. R. Anderson & C. Davis and Stigmaphyllon sagranum A. Juss. are abundant.

Conservation status — The population of Picrasma pauciflora comprises fewer than 20 individuals in an area of 400 m² growing near to a path that crosses the forest. For this reason the only known population of the species could disappear after the occurrence of stochastic meteorological events like hurricanes or by human activities such as logging, accidental fires or wrong management of the forest where it grows. Taking into account this situation and according to IUCN criteria (IUCN 2012), P. pauciflora must be classified as Critically Endangered: CR B1ab(iii,v)+2ab(iii,v); D.

Etymology — The specific name refers the presence of few flowers in the inflorescences.

Additional specimens seen — Cuba: province of Holguín: municipality of Rafael Freyre: Loma El Templo, al oeste de la Bahía de Naranjo, 17 Oct 1978, A. Álvarez de Zayas, J. Bisse, A. Borhidi, L. Catasús, A. López & T. Pócs, HFC 38198 (B, HAJB; plus 2 sheets at JE not seen, H. Manitz, pers. comm.).