Piper claseanum Bornst., 2014

Bornstein, Allan J., Smith, James F. & Tepe, Eric J., 2014, Two New Species of Piper from the Greater Antilles, Systematic Botany (Basel, Switzerland) 39 (1), pp. 10-16 : 14-15

Piper claseanum Bornst. , sp. nov.

— TYPE: DOMINICAN REPUBLIC. Province of Azua: Sierra Martín García, 11.2 km from Hwy. 44, ca. 8 km W of El Cruce de Quince , S of Tábara Abajo , Los Manantiales , 18 23 ' 01 '' N, 70 59 ' 09 '' W, 810 m, 10 January 2012, A. Bornstein, E. Tepe, and T. Clase 1283 (holotype: JBSD; isotypes: MO, MU, SEMO).

Medium-sized, multi-branched shrub, ca. 1.7–3.0 m tall, stems with thickened nodes; leafy internodes 0.8–4.6 cm long (mean = 1.82 cm, median = 1.75 cm; N = 40), smooth, dark brown to black, and glabrous to puberulent when young, becoming striate to canaliculate, pale gray-brown, and bearing numerous warty lenticels with age. Immature prophylls 0.90–1.50 mm long (mean = 1.26 mm, median = 1.35 mm; N = 9), apex angle acute, apex shape convex, rounded, glabrous, drying dark brown to black. Leaves with petioles 1.30–4.50 mm long (mean = 2.47 mm, median = 2.40 mm; N = 40), glabrous to puberulent, vaginate at the base and lacking a stipule-like structure at all nodes; lamina 3.5–5.9 cm long (mean = 4.75 cm, median = 4.90 cm; N = 39) and 1.9– 4.4 cm wide (mean = 2.74 cm, median = 2.60 cm; N = 39), elliptic, broadly elliptic, or oblong-elliptic, occasionally obovate, medially symmetrical, apex angle acute to obtuse, apex shape straight, rounded, or acuminate, base symmetrical with two black, gland-like callosities present, one on each side of the petiole, base angle acute, base shape convex to rounded, venation palmate with 3 major veins organized in basal, acrodromous pattern, coriaceous and with numerous pellucid dots visible abaxially upon drying, smooth on both surfaces, glabrous, dark green adaxially, pale green abaxially. Racemes erect at all stages and free of the leaf base, white at anthesis and in fruit; peduncles 0.30–0.95 cm long (mean = 0.55 cm, median = 0.55 cm; N = 40), glabrous to sparsely puberulent; rachis 1.20–4.85 cm long (mean = 2.87 cm, median = 2.75 cm; N = 40) and 0.4–0.8 (1.2) mm wide (mean = 0.60 mm, median = 0.60 mm; N = 40) when dry, puberulent; floral bracts 0.200 – 0.475 mm wide (mean = 0.31 mm, median = 0.30 mm; N = 40), cucullate in general outline, glabrous; flowers loosely organized (widely spaced) along rachis, not forming distinct bands around the axis, pedicellate, the pedicels gradually broadening to the apex, 1.3–4.2 mm long (mean = 2.66 mm, median = 2.60 mm; N = 40), puberulent; stamens 5–7, borne at top of pedicel immediately below ovary, anthers laterally dehiscent (measurements not available due to very limited material). Fruits white at maturity, ovoid to globose, 2.0– 3.2 mm long (mean = 2.68 mm, median = 2.70 mm; N = 20) and 2.1–3.8 mm wide (mean = 3.14 mm, median = 3.20 mm; N = 20), glabrous to sparsely puberulent, stigmas 2–4, broad, sessile. Figure 3 .

Additional Specimens Examined— DOMINICAN REPUBLIC. Azua: Sierra Martín Garciá, Distrito municipal Tábara Abajo , en un lugar denominado Los Manantiales , 203866 N, 290281 E, 760 m, 19 Feb 2008, B. Peguero & T. Clase 4267 and 4268 ( JBSD, SEMO).

Notes— Piper claseanum is apparently endemic to the southcentral mountain range known as Sierra Martín García in the province of Azua in the Dominican Republic. It grows in shaded sites on steep, rocky hillsides from 700–850 m elevation. Plants were in late flower or mature fruit in January, so it is likely to be in full flower in November and December, with fruits persisting into February or March; additional collecting at these times would be necessary for confirmation, and similar efforts in other months would be helpful to determine if year-round flowering and fruiting occurs. The epithet claseanum is in honor of Teodoro Clase, long-time student of the flora of the Dominican Republic and one of the initial individuals to recognize this new species.

Piper claseanum belongs to clade Enckea , which includes a group of species with palmately veined leaves and the usual presence of two basal callosities at the petiole/lamina junction, erect inflorescences with the flowers, fruits, and associated bracts usually loosely organized around the inflorescence and not forming distinct bands, bracts sessile or short-pedicellate, cucullate in overall shape, and the fruits globose, ovoid, or flask-shaped. This species is most closely related to Piper samanense Urban based on molecular data ( Fig. 1 ), and in vegetative condition appears similar due to the relatively small, leathery leaves with three primary veins and the numerous pellucid dots evident upon drying. They also share the unusual white fruit color, which appears to be a synapomorphy for these taxa. The two species can be easily distinguished because P. samanense has more densely packed flowers along the densely white-pubescent (vs. puberulent) rachis, the pedicels are shorter and broader, and only develop if the fruit matures (= pseudo-pedicellate), the fruits are more densely puberulent to pubescent, and the stigma lobes are quite narrow.

It is also interesting to note that the endemic species of Enckea from the Greater Antilles form a clade that is sister to the largely continental taxa (only the widespread Piper amalago L. and P. reticulatum L. occur in the Antilles). Further sampling of the enckeoid species endemic to Cuba [e.g. Piper lindenianum C. DC. , P. mananthum C. Wright , P. perditum Trel. , and P. sphaerocarpum (Griseb.) C. DC. ex C. Wright ] and Haiti ( P. sinuatispicum Trel. and P. perpallidum Ekman, Urb. & Trel. ) would be necessary to confirm if this pattern holds.

The following key can be used to identify P. claseanum and other palmate-veined species from the Dominican Republic.

Figures

FIG. 3. Piper claseanum Bornstein. A. Branch with leaves and inflorescence. B. Abaxial leaf surface to indicate lack of pubescence and minute pellucid dots. C. Fruit with pedicel and associated bract. Drawn from field observations, pressed and liquid-preserved material from Bornstein et al. 1283.

FIG. 1. A 50% majority rule tree of the genus Piper from the bootstrap analysis using maximum parsimony (213 trees of 4,336 steps each, consistency index = 0.3536, retention index = 0.7550, rescaled consistency index = 0.3195), with emphasis on clades Radula and Enckea to demonstrate placement of the two new species, Piper abajoense and Piper claseanum. Note that other major clades of Piper (indicated in italicized capital letters) have been collapsed, but contain the same species as Jaramillo et al. (2008).