Pilea matthewii Dorr & Stergios, 2014

Dorr, Laurence J. & Stergios, Basil, 2014, Four new species of Andean Pilea (Urticaceae), with additional notes on the genus in Venezuela, PhytoKeys 42, pp. 57-76 : 59

Pilea matthewii Dorr & Stergios sp. nov. Figure 1

Pilea sp. A; Dorr et al., Contr. U.S. Natl. Herb. 40: 146. 2000 [2001].

Diagnosis.

Pilea matthewii resembles Pilea crugeriana Wedd. from which it differs by having simple (versus 3-rayed) foliar cystoliths and shortly pedicellate (versus sessile) staminate flowers.

Type.

VENEZUELA. Trujillo: Mpio. Boconó: Páramo de Guaramacal, SE of television towers, ca 09°14'N, 070°11'W, 2000 m, 28 Apr 1988, L.J. Dorr et al. 4994 (holotype (♀): PORT [39536]; isotypes (♀): NY, US (excluding ♂ branchlet) [00534984], VEN).

Description.

Herb, 30-80 cm tall; terrestrial; dioecious. Stems erect, succulent, branched, drying dark grayish-brown or almost black, glabrous, cystoliths fusiform to elliptic or absent, internodes 7-50 × 1-3 mm (shorter and narrower distally), terete, somewhat angular in cross-section when dry. Stipules ca 0.5-1 mm long, broadly deltate, drying dark brown with lighter brown margins, persistent. Leaves petiolate, distichous; petioles at each node unequal by a ratio of 1:3-24; major petioles 3-15 (-20) mm long, canaliculate above, glabrous; minor petioles 0.5-1 mm long or subsessile, canaliculate above, glabrous; laminae at each node unequal by a ratio of 1:3.1-11.1; major laminae in a pair 2.2-11.5 × (0.8-) 1.2-2.7 cm, lanceolate or elliptic, slightly falcate, sub-chartaceous to chartaceous, 3-nerved from the base, midrib and lateral nerves prominent below, lateral nerves visible almost the entire lamina length but disappearing just below the apex, secondary nerves 8-16 pair, borne 70-80 (-90)° to the midrib and then strongly curved distally, upper surface drying dark grayish-brown or almost black, glabrous except for scattered, minute, orange-brown peltate scales, cystoliths fusiform or absent, lower surface drying dark greenish- or reddish-brown, glabrous, base slightly asymmetrical, cuneate, margin regularly toothed, apex acuminate; minor laminae in a pair 0.7-2 × 0.4-1.5 mm, ovate to broadly-ovate, base slightly asymmetrical, auriculate, apex abruptly acuminate, otherwise as major laminae. Inflorescences 8-10 per stem, unisexual; bracts ca 0.75-1 mm long; bracteoles ca 0.75 mm long. Staminate inflorescences (1) 2 per axil, 6-12 mm long, bearing 12-25 flowers in a lax cyme; peduncles 1.5-7 mm long, usually shorter than major petioles, occasionally with cystoliths and/or minute, peltate scales present, otherwise glabrous; pedicels ca 0.5 mm long, glabrous. Staminate flowers ca 1.5 × 1 mm immediately prior to anthesis, whitish-green; tepals 4, ca 1.5 mm long, occasionally cystoliths present and often minute, peltate scales present at base, otherwise glabrous, the subapical appendages unequal, ca 0.25 mm long, corniculate, glabrous; stamens 4. Pistillate inflorescences (1) 2 per axil, ca 3 mm long, bearing 10-26 flowers in a congested cyme; peduncles ca 1-15 mm long, glabrous; pedicels 0.25-1 mm long, glabrous. Pistillate flowers ca 1-1.25 mm long; cucullate tepal ca 1-1.25 mm long, ± lanceolate, appendage ca 0.25 mm long; lateral tepals ca 1-1.25 mm long, narrowly ovate. Infructescences 8-17 (-29) mm long; peduncles 5-13 (-23) mm long; achenes ca 1-1.5 × 0.5-1 mm, compressed, asymmetrically ellipsoid or lachrymiform, verrucose, margin narrowly thickened.

Distribution and ecology.

Known only from the Andes of Venezuela (Portuguesa and Trujillo states) where it is found in the understory of cloud forest; 1000-2600 m.

Etymology.

The epithet recognizes Matthew Dorr who participated in a number of expeditions to Guaramacal in search of specimens for the Flora of Guaramacal project (PORT-US).

Specimens examined.

VENEZUELA. Portuguesa: Mpio. Sucre: Parque Nacional Guaramacal, Sector El Paramito, Camino Real Paramito - Batatal, 09°19,03'N, 070°04,25'W to 09°20,35'N, 070°04,08'W, 1550-1950 m, 17 Mar 1999, N. Cuello et al. 1470 (PORT, US); Los Paramitos, a 20 km por aire al SO de Biscucuy, a orillas de la quebrada El Alto tambien conocida como La Lora, 09°20'N, 069°05'W, 1000-1500 m, 17 Sep 1983, B. Stergios et al. 6340 (PORT); La Divisoria de la Concepción, 09°18'N, 070°06'W, 1700 m, 23 Oct 1985, H. van der Werff et al. 7560 (PORT). Trujillo: Mpio. Boconó: linderos del Parque Nacional Guaramacal, Laguna de Agua Negra, 09°18'N, 070°10'W, 1840 m, 27 Oct 2001, J. Angulo & J. Infante 17 (PORT); 2 km al N-O del Caserío Cerros de Guaramacal, 42 km al S-E de Boconó, ca 09°11'N, 070°10'W, 1500 m, 25 Jul 1984, G. Aymard & F. Ortega 2903 (PORT); Limites del Páramo de Guaramacal y el bosque nublado, 25 km al S-E de Boconó, ca 09°13'N, 070°10'W, 2200-2600 m, 26 Jul 1984, G. Aymard et al. 2954 (NY, PORT); Parque Nacional Guaramacal, Sector Las Cruces, Camino Real La Aguadita - Batatal, 09°20,11'N, 070°05,57'W, 1900-1950 m, 17 Mar 1999, N. Cuello et al. 1486 (PORT, US), Ibid., N. Cuello et al. 1498 (NY, PORT, US); P.N. Guaramacal, "El Campamento" below Cerro El Diablo, ca 10 km S of Boconó on road from Fundación La Salle to El Santuario, 09°09'N, 070°17'W, 1910 m, 21 Jul 1995, L.J. Dorr et al. 8192 (G, K, NY, PORT, US, VEN); Parque Nacional Guaramacal, trail from la Laguna de las Aguas Negras to la Qda. Salvaje, N slope of mountain, 09°19'N, 070°11'W, 27 Oct 1998, L.J. Dorr et al. 8292 (K, PORT, US); Parque Nacional Guaramacal, road from Boconó to Guaramacal, SE of Boconó, ca 15 km from the post of the park guards, 09°13'N, 070°12'W, 2 Nov 1998, L.J. Dorr et al. 8404 (PORT-unicate), Ibid., L.J. Dorr et al. 8407 (K, MO, PORT, US); Parque Nacional Guaramacal, trail from El Cafenol (E of Mosquey) to Fila Los Recostaderos, 1790-2200 m, 12 Jun 2001, L.J. Dorr et al. 8924 (K, PORT, US); 12 km ESE of Boconó, 1 km N to 4 km NE of Guaramacal, 09°12' to 09°13'N, 070°09'W, 1600-1900 m, 15 Mar 1982, R. Liesner et al. 12947 (PORT, VEN), Ibid., R. Liesner et al. 12998 (PORT, VEN), Ibid., R. Liesner et al. 13019 (PORT, VEN); Parque Nacional Guaramacal, sector El Santuario, "La Punta," 1860 m, 9-16 Jul 1998, B. Stergios 17348 (PORT, US), Ibid., B. Stergios 17401 (K, NY, PORT, US); Parque Nacional Guaramacal, sector El Santuario, vertiente y cresta-divisoria entre qbda. Honda y qbda. Kubiscú, 2000-2300 m, Jan 2001, B. Stergios & R. Caracas 19064 (K, PORT, US); Parque Nacional Guaramacal, sector vertiente sur, Aug 2001, B. Stergios & R. Caracas 19301 (PORT, US); Cerro Guaramacal, Boconó, bajando hacia el caserío de Guaramacal, 25-26 Nov 1982, B. Stergios et al. 4700 (PORT, US); Parque Nacional Guaramacal, trail from Casa Vicuyal toward Páramo de Vicuyal, 2200-2600 m, 10 Apr 2003, B. Stergios et al. 20080 (K, MO, NY, PORT, US); Parque Nacional Guaramacal, Casa Vicuyal, 2100 m, 12 Apr 2003, B. Stergios et al. 20182 (K, MO, NY, PORT, US); Parque Nacional Guaramacal, SE slopes of Cerro Guaramacal on road from Boconó to Guaramacal, Qda. Pollo, 09°13'N, 070°10'W, 2200 m, 22 Sep 2003, B. Stergios et al. 20668 (K, MO, NY, PORT, US). Parque Nacional Guaramacal, "El Campamento," below Cerro El Diablo and vicinity, 1800-2000 m, 16-18 Aug 2005, B. Stergios et al. 20859 (K, PORT, US).

Discussion.

Pilea matthewii belongs in the Heterophyllae species group of Weddell (1869) and the Centradenioideae species group of Killip (1936). The new species most closely resembles Pilea crugeriana of the Coastal Cordillera of Venezuela, but it is readily distinguished by its simple (versus 3-rayed) cystoliths and shortly pedicellate (versus sessile) staminate flowers. Other characters that separate these two species are given in Table 1 .

Conservation status.

Using IUCN criteria ( IUCN 2001) we could not identify a threat to Pilea matthewii . We are aware of 15-20 distinct populations in Guaramacal National Park, which protects an area of 225 km2. Although this area is relatively small, the species is frequently encountered and the number of known populations exceeds the number of locations deemed critical under IUCN criterion B2(a) for either Endangered (E) or Vulnerable (VU). In addition, the east-facing slopes of the Sierra Nevada de Mérida, which have similar habitat, are very poorly collected ( Dorr et al. 2005) and might harbor additional populations of this species.