Pilea miguelii 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 : 59-60

Pilea miguelii Dorr & Stergios sp. nov. Figure 2

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

Pilea sp. B, vel aff., Dorr et al., Contr. U.S. Natl. Herb. 40: 146. 2000 [2001].

Diagnosis.

Similar to Pilea haenkei Killip in the extreme difference in size of leaf laminae at each node, but differing in lamina shape (narrowly ovate to ovate or obovate versus ovate-lanceolate) and base (asymmetrically cuneate versus cordate).

Type.

VENEZUELA. Trujillo: Mpio. Boconó: "Laguna Negra," carretera entre Batatal y Mosquey, 1700 m, 3 Apr 1994, B. Stergios & M. Niño 16028 (holotype: PORT [58122]; isotypes: NY, US [00727846]).

Description.

Herb or shrublet, to 1.5 m tall; terrestrial; monoecious. Stems erect, branched, ± suffruticose, drying dull green or dark blackish-brown, glabrous, cystoliths fusiform, sometimes very dense, internodes 2.3-11 cm × 2-3 mm (shorter distally), terete and becoming ± angulate in cross-section when dry. Stipules ca 2 mm long, deltoid, drying light-brown, caducous. Leaves petiolate, distichous; petioles at the same node unequal by a ratio of 1:(5-) 10-20, major petioles 0.5-4 cm long, minor petioles ca 1 mm long or subsessile, glabrous; laminae of leaves at each node unequal by a ratio of 1:5-11.5; major laminae in a pair 5-11.5 × 2-5.5 (-7) cm, narrowly ovate to ovate or obovate, slightly asymmetric, membranous, 3-nerved from the base or lateral nerves diverging from the midrib 1-2 mm above the base, secondary nerves 12-14 pair, borne 80-90° to the midrib; upper surface dull or dark green, glabrous, cystoliths fusiform, unequal in size, often dense, lower surface pale or dull green, glabrous, midrib and secondary nerves prominently raised, base asymmetrically cuneate, margin coarsely crenate to serrate its entire length, apex long acuminate; minor laminae in a pair 0.9-2 × 0.5-1 cm, otherwise as major laminae. Inflorescences> 20 per stem, unisexual, white, whitish-green or green; bracts broadly deltate, ca 1 mm long; bracteoles broadly deltate, ca 1 mm long. Staminate inflorescences 4 per axil, 10-15 × 17-20 mm, bearing> 50 flowers in a loose, spreading cyme; peduncles 2-5 mm long, glabrous; pedicels ca 0.5-1 mm long, glabrous. Staminate flowers ca 1 mm long, greenish-white; tepals 4, ca 0.75 mm long, ± verrucose; stamens 4. Pistillate inflorescences 4 per axil, ca 10 × 18 mm, bearing> 50 flowers in a loose, spreading cyme; peduncles 2-5 mm long, glabrous; pedicels 0.5-0.75 mm long, glabrous. Pistillate flowers ca 0. 5 mm long. Infructescences not seen.

Distribution and ecology.

Known only from the Andes of Venezuela (Lara, Mérida, and Trujillo states) where it forms colonies in the understory of cloud forest; 1490-2600 (-3210) m.

Etymology.

This species is named for S. Miguel Niño, professor at UNELLEZ, Guanare, and valued collaborator in our investigations of the Andean flora.

Specimens examined.

VENEZUELA. Lara: Mpio. Morán: Quebrada Los Cedros (09°31'N, 070°01'W), 15 km al S de Humocaro Alto, hacia Guaitó, 1500 m, 8 Jul 1974, J.A. Steyermark & V. Carreño Espinoza 110270 (VEN). Mérida: Mpio. Arzobispo Chacón: NW- and W-facing slopes of Quebrada de Montaña, in La Montaña de Los Torritos, tributary to Río Canaguá, above Finca La Montaña, 8 km SW of Canaguá, 1925-2075 m, 8 May 1944, J.A. Steyermark 56365 (US). Mpio. Rangel: Quebrada entre Aracay y La Cuchilla, 08°56'N, 070°36'W, 2250 m, 28 Dec 1985, A. Fernandez 1582 (PORT). Mpio. Libertador: between Los Corales and Las Cuadras, 1490-3210 m, 25 Mar 1944, J.A. Steyermark 55767 (US). Trujillo: Mpio. Boconó: Límites del Páramo de Guaramacal y el bosque nublado, 25 km SE de Boconó, ca 09°13'N, 070°10'W, 2200-2600 m, 23 Jan 1986, G. Aymard et al. 5000 (PORT); Parque Nacional Guaramacal, en los alrededores del acueducto de Boconó, detras de la Laguna de Los Cedros, 09°14'38"N, 070°13'12"W, 1850 m, 12 Mar 1998, N. Cuello et al. 1399 (PORT, US); Parque Nacional Guaramacal, vertiente occidental, Sector El Santuario, alrededores de La Cueva, ca 09°10'N, 070°18'W, 1800 m, 1 May 1998, N. Cuello et al. 1432 (NY, PORT, US); 13 km ESE of Boconó, 1 km W of Guaramacal, 09°11'N, 070°09'W, 1600 m, 16 Mar 1982, R. Liesner et al. 12896 (MO, PORT, VEN). Entre Boconó y El Batatal, 1800 m, 5 Sep 1966, J.A. Steyermark & M. Rabe 97410 (NY, US, VEN).

Discussion.

Pilea miguelii belongs in the Heterophyllae species group of Weddell (1869) and the Centradenioideae species group of Killip (1936). The new species is easily recognized by the combination of the extreme difference in leaf laminae size at each node and the branching inflorescences.

One of the specimens (Steyermark 56365, US) that fits our concept of Pilea miguelii was identified by Killip (in sched.) as Pilea losensis Killip, but the similarity is superficial. Killip (1936) included Pilea losensis in his Multiflorae species group and unlike our new species the leaf laminae at each node are ± equal in size (versus distinctly unequal), the laminae are narrowly elliptic to oblong-elliptic (versus narrowly ovate to ovate or obovate), and the apices are acuminate (versus long acuminate). In addition, the type of Pilea losensis , at least, is sparingly branched while most collections of Pilea miguelii are profusely branched.

Another specimen (Steyermark 55767, US) that fits our concept of Pilea miguelii was identified by Killip (in sched.) as Pilea carnosula Wedd., also in his Multiflorae species group ( Killip 1936). This "new record" for Venezuela was reported by Steyermark (1957 as " carnulosa ") and subsequently repeated by Romaniuc Neto (2008 as " carnulosa "). The two species are only superficially similar. The leaf laminae at each node are ± similar in size in Pilea carnosula and the major laminae of Pilea carnosula are smaller than those of Pilea miguelii (0.8-4 versus 5-11.5 cm long).

The very dense, whitish covering of cystoliths on the leaves and stems of one collection (Steyermark & Rabe 97410) from Trujillo makes the material look different than the type of Pilea miguelii , but a careful examination of other morphological characters (leaf size, shape, venation, etc.) convinces us that this sterile collection belongs with Pilea miguelii as does another sterile collection (A. Fernandez 1582) from Mérida that also has a dense covering of cystoliths.

Table 2 summarizes the differences between Pilea miguelii and other species to which it is compared (see diagnosis) or with which it has been confused.

Conservation status.

We cannot discern a threat to Pilea miguelii using IUCN criteria ( IUCN 2001). We are aware of 15-20 distinct populations, all but one of which is in either Guaramacal National Park or the Sierra Nevada National Park. The extent of occurrence (EOO) is less than 5000 km2 and the area of occupancy (AOO) is less than 500 km2, which might suggest that the species is Endangered (E) under criteria B1 or B2, but there are> 5 populations and no evidence of their decline.