Piper abajoense Bornst., 2014

Piper abajoense Bornst. View in CoL , sp. nov.

— TYPE: PUERTO RICO. Municipality of Utuado: Río Abajo Forest Reserve , near electric power station along road (Hwy 621) beyond the ranger station, 18 20 ' N, 66 43 ' W, 315 m, 10 January 2011, A. Bornstein, H. Schubert, and F. Axelrod 1250 (holotype: UPRRP; GoogleMaps isotypes: MO, SEMO). GoogleMaps

Medium-sized, multi-branched shrub, ca. 1.5–3.0 m tall, stems with thickened nodes and diam up to 4–5 cm on welldeveloped specimens; leafy internodes 1.5–5.3 cm long (mean = 3.15 cm, median = 3.20 cm; N = 54), pubescent with multicellular hairs up to 0.75 mm long. Prophylls 0.90–2.45 cm long (mean = 1.84 cm, median = 2.00 cm; N = 8), apex angle acute, apex shape straight, glabrous except for pubescent along midvein region abaxially with multicellular hairs up to 0.75 mm long, caducous and usually drying dark brown to black. Leaves with petioles 0.20–1.20 cm long (mean = 0.49 cm, median = 0.45 cm; N = 41), pubescent with multicellular hairs up to 0.75 mm long, vaginate near the base and with a stipule-like structure present at flowering nodes, 1.0– 2.5 mm long, densely ciliate; lamina 10.8–19.2 cm long (mean = 15.52 cm, median = 15.60 cm; N = 35) and 3.5–7.3 cm wide (mean = 5.78 cm, median = 5.95 cm; N = 38), elliptic to oblong-elliptic, medially symmetrical, apex angle acute, apex shape straight to often acuminate, base symmetrical to most commonly slightly asymmetrical, the two sides inserted 0.0– 0.6 mm apart (mean = 0.32 mm, median = 0.35 mm; N = 41), base angle acute, base shape convex to rounded, venation pinnate with 4–5 pairs of secondary veins arising along lower 2 /3 of midvein, the central vein and two uppermost secondary veins extending to tip of apex, drying thin-chartaceous and with numerous pellucid dots visible below (at least upon drying), smooth to slightly scabrous adaxially, but moderately pubescent along midvein and secondaries with multicellular hairs, pubescent abaxially, especially along the primary and secondary veins, with multicellular hairs up to 0.75 mm long. Spikes erect at all stages and free of the leaf base, yellowish at anthesis, becoming green in fruit, sometimes with sterile tip to 2.5 mm long; peduncles 0.9–2.0 cm long (mean = 1.31 mm, median = 1.30 mm; N = 22), pubescent with multicellular hairs 0.5–0.6 mm long; rachis 4.35– 6.60 cm long (mean = 5.71 cm, median = 5.78 cm; N = 22) and 3.0–6.0 mm wide (mean = 4.21 mm, median = 4.0 mm; N = 21) in fruit, glabrous; floral bracts 0.3–0.8 mm wide (mean = 0.51 mm, median = 0.50 mm; N = 55), roundedtriangular in general outline, glabrous centrally but densely fimbriate along entire margin; flowers densely grouped along rachis, forming distinct bands around the spike, sessile; stamens 3, anthers 0.250 –0.425 mm long (mean = 0.30 mm, median = 0.30 mm; N = 50), with lateral dehiscence. Fruits narrowly obovoid, round to somewhat angular in apical view, flattened laterally, 1.2–1.7 mm long (mean = 1.594 mm, median = 1.60 mm; N = 20) and 0.65–1.10 mm wide (mean = 0.892 mm, median = 0.90 mm; N = 25), glabrous or sparsely pubescent near apex, stigmas 2 or 3, elongate, recurved, borne on a style ca. 0.5 mm long within a central depression. Figure 2 View FIG .

Additional Specimens Examined— PUERTO RICO. Arecibo: Bosque Río Arriba, along 1 km stretch at S end of pilot road for Rt. 10, 18 20.33 ' N, 66 40.67 ' W, 250–275 m, 1 June 1994, F. Axelrod & B. Waide 7816 ( UPRRP) GoogleMaps ; Bosque Río Arriba , in sinkhole 1 km along S end of pilot road for Rt. 10, 18 20.33 ' N, 66 40.67 ' W, ca. 225 m, 1 June 1994, F. Axelrod & B. Waide 7818 ( UPRRP) GoogleMaps ; Bosque Río Arriba , Río Abajo Forest Reserve , on slopes of sinkhole about 2 km N of S end of pilot road for proposed Rt. 10, 18 20.86 ' N, 66 41.00 ' W, 275 m, 22 July 1994, F. Axelrod & L. Pérez 8062 ( UPRRP) GoogleMaps ; Bosque Sabana Hoyos , Finca Las Abras, forested abra between mogotes, 18 20.19 ' N, 66 33.13 ' W, ca. 300 m, 21 September 2002, J. C. Trejo-Torres et al. 1788 ( UPRRP). GoogleMaps Isabela: Bosque Arenales Altos , sinkhole near and W of road 112 at km 9, ca. 18 25.129 ' N, 67 02.093 ' W, 150 m, 19 July 2006, J. C. Trejo et al. 3065 ( UPRRP). GoogleMaps Utuado: Bosque Santa Rosa, Río Abajo Forest Reserve , along Las Perdices Trail, ca. 350 m, 11 August 1993, F. Axelrod 6807 ( UPRRP) ; Río Abajo Forest Reserve, ca. 100 m past electric power station along old logging road S of road 621, ca. 2.5 km beyond the María Soto campground, 18 20 ' N, 66 43 ' W, 315 m, 10 January 2013, A. Bornstein, C. Wisniewski, and D. Wood 1288 ( MO, NY, SEMO, UPRRP) GoogleMaps ; Río Abajo Forest Reserve , S of road 621, fourth mogote if coming from reserve office, June 1999, J. C. Trejo-Torres & A. Alicea 1394 ( UPRRP) ; Orcovis: Hwy 143 at Verada La Torre , Toro Negro Recreation Area , growing along stream below pool area, 18 10 ' N, 66 29 ' W, 890 m, 14 January 2011, A. Bornstein & H. Schubert 1267 ( MO, NY, SEMO, UPRRP) GoogleMaps .

Notes— Piper abajoense occurs in the northern limestone hills (mogotes) and central mountains of Puerto Rico. It grows in partially shaded sites along forest edges or in cleared, disturbed areas between 200–900 m elevation. Plants were in both flower and fruit in January, and late flower into full fruit from June to September; they are likely to flower and fruit throughout the year. The epithet abajoense is in reference to the main location where it has been collected (Río Abajo Forest Reserve), a wonderful nature preserve where all of the Piper species in Puerto Rico are known to co-occur.

Piper abajoense belongs to clade Radula (see Fig. 1 View FIG ), which is a monophyletic group of species distinguished by the presence of pinnately veined leaves, typically erect inflorescences with the flowers, fruits, and bracts forming distinct bands around the spikes, bracts often fimbriate-margined and lacking an umbo, lack of basal callosities at the junction of the lamina and petiole, and fruits triangular or rounded. In Puerto Rico this species most closely resembles Piper hispidum Sw. , but can be distinguished by the ± glabrous fruits (vs. apically densely puberulent), stylose (vs. estylose) ovary and young fruits, laterally (vs. apically) dehiscent anthers, and shorter inflorescences (<8 cm vs. 10 + cm).

The following key can be used to identify P. abajoense and the other 10 species of Piper known from Puerto Rico.