Alchornea tenuinervia J.Murillo, 2018

Murillo-Aldana, José, 2018, Novelties in the genus Alchornea (Euphorbiaceae), Phytotaxa 375 (3), pp. 203-213 : 208-211

Alchornea tenuinervia J.Murillo , sp. nov. ( Fig. 3 )

Alchornea . tenuinervia resembles A. guatemalensis and A. integrifolia with regard to its leaves, but it differs by having leaves with serrate margins, semicraspedromous, brochidodromous or eucamptodromous pinnate venation, up to 10 pairs of secondary veins, inconspicuous higher orders of venation, and unbranched or shortly few-branched inflorescences.

Type: ― COLOMBIA. Antioquia: Anorí, Corrg. Providencia, valle del río Anorí, entre Dos Bocas y Anorí, camino entre Providencia, Popales y quebrada Tirana, 400–900 m, 24–31 May 1973 (fl), D.D. Soejarto, J. L. Zarucchi, T. Swain & J. Bagley 4118 (holotype COL!, isotype MO).

Shrubs or trees 2–15 m high, adult branches and petioles glabrous, young branches, and the petioles abundantly covered with rotate-stellate trichomes, ca. 0.1 mm in diam., with 4–12 rays. Leaves alternate; stipules ovate-triangular, 0.5–1.0 mm long; petioles 0.2–1.2 cm long, upper side grooved; blade obovate, sometimes elliptical, 5–10(–11) × 2–4(–5.5) cm, coriaceous, apex rounded, sometimes acuminate, margin serrate with teeth glandular teeth, base obtuse to round or sometimes acute, 0–2 basilaminar glandular spots on the upper side, (0–)2–4(–5) spots on the lower side, sometimes with a pair of laminar, medial glandular spots; upper side glabrous, lower side lightly to moderately covered with rotate stellate trichomes, ca. 0.1 mm in diam., with (4–)8–12 rays; domatia pits and enclosing hair-tufts, or sometimes just hair-tufts present in the axils of the secondary veins; venation semicraspedodromous pinnate, sometimes brochidodromous to eucamptodromous; secondary veins in 5–8(–10) pairs, flat to slightly elevated on the upper side, generally not conspicuous on the lower side; tertiary veins percurrent, oblique, inconspicuous. Staminate inflorescences unbranched or sometimes branched with sparse branching, axillary, 2.5–8.0(–10) cm long, solitary or sometimes fasciculate, peduncle (0.2–)1.0– 2.5 cm long, axis ca. 0.1 cm in diam., covered abundantly with rotate stellate trichomes, ca. 0.1 mm in diam.; flowers clusters of up to 5 per node, internodes 1–5 mm long, bracts of clusters widely ovate, 0.5–0.7 mm long; pedicels ca. 0.7 mm long, buds 1.2–1.5 mm wide, glabrous, sometimes sparsely covered with rotate or multiangular stellate trichomes; sepals 2, partly fused; stamens 8, connate at the base, glabrous, anthers ca. 0.7 mm long. Pistillate inflorescences unbrached, axillary, solitary, 2.0– 4.5 cm long, peduncle 0.5 cm long, moderately covered with rotate stellate trichomes, ca. 0.1 in diam.; flowers solitary, subsessile; bract widely ovate, ca. 0.5 mm long; sepals 4, partly fused, lobes 0.5–1 mm long, apex acute; ovary 1.0– 1.5 mm long, moderately covered with rotate stellate trichomes, 2–locular, styles connate at the base, 5–7 mm long, filiform, stigmas finely rugose. Fruit bilobed, 0.3–0.6 × 0.7 cm; seed ellipsoid, 4–5 × 4–5 × 3.0– 3.5 mm, tuberculate, brown, aril red.

Distribution: —This species has been collected in the departments of Antioquia, Bolivar, Huila, Meta, and northern Santander at elevations between 400 and 1300 (–1700) m.

Phenology:—This species is fertile between January and April and in August and October.

Common name: —Escobo (Antioquia)

Etymology: —This specific epithet refers to the fact that the secondary veins are not pronounced and the tertiary veins are inconspicuous.

Notes: —This species is characterized by petioles up to 1.2 cm long, mostly obovate leaf blades with usually rounded apices, domatia consisting of pits and enclosing hair-tufts, non-pronounced secondary veins, and inconspicuous tertiary veins. Variations in leaf shape and apex are present, as in Cárdenas 2748 (HUA) and Phillipson 2315 (COL), which have elliptical and acuminate blades, rather than the typical obovate and rounded, but in Idrobo 1303 (COL) and Sánchez 8163 (HECASA) both shapes occur. Alchornea tenuinervia is similar to A. guatemalensis Lundell (1978: 10) with respect to the leaf shape but differs sufficiently because in A. guatemalensis the leaves are entire, the venation is acrodromous, and there are fewer secondary veins (3–4 vs. 5–10). This species could also be confused with A. integrifolia Pax & Hoffmann (1914: 237) with regard to several characters of the leaves, but these two species differ in leaf margin (entire vs. serrate), venation (acrodromous vs. semicraspedodromous to brochidodromous pinnate), number of secondary veins (4–6 vs. 5–10), and staminate inflorescence (branched vs. not sparsely branched).

Additional specimens examined (paratypes): — COLOMBIA. Antioquia: Anorí, vereda El Zafiro, sector Chica, 7 ° 3´13.14”N, 75 ° 7´30.78”W, 1701 m, 2 December 2010 (fl), A. Taborda & L. Londoño 601 ( HUA) ; Vereda Puerto Rico , 7 ° 8´20”N, 75 ° 8´20”W, 800-900 m, 12 October 1999 (fl), D. Tuberquia 1325 ( COL, JAUM) ; Vereda Concha Abajo 7 ° 15´N, 75 ° 09´W, 650 m, L. Vera 249 ( MEDEL) ; San Luis, Vereda La Josefina, quebrada La Mariola, 6 ° 0´N, 74 ° 55´W, 700–925 m, 12 April 1990 (fl, fr), D. Cárdenas & J. Ramírez 2748 ( HUA). Bolívar: Santa Rosa, Guamoco, caserío Tomates, 7 ° 38´29”N, 74 ° 28´57”W, 884 m, 12 May 2010 (ster), W. Rodríguez 6803 ( MEDEL). Huila: Aipe, vereda San Antonio, 1224 m, A. Bohórquez 644 ( FAUC). Meta: serranía de La Macarena, mesa del Río Sansa , 1000–1300 m, 23 January 1951 (fl), J. Idrobo 1303 ( COL) ; Northern escarpment, 800 m, 30 January 1950 (fl), W. R. Philipson 2284 ( COL) ; 1 February 1950 (fr), W. R. Philipson 2315 ( COL). Norte de Santander: Bochalema, borde de la carretera que sale a Cucutilla , vereda Las Ventas , desde cerca del pueblo hasta km 6, 1300 m, 17 February 2001 (fl, fr), R. Sánchez 5288 ( HECASA) ; Pamplonita, Santa Lucia, 1350 m, 31 October 2003 (fl), R. Sánchez 8163 ( HECASA) .

Alchornea verticillata P. Francô & Rentería ex J.Murillo, sp. nov. ( Fig. 4 )

This species is characterized by leaves arranged in whorls of three, petioles less than 3 cm in length, domatia generally absent, and the lower surface of the blade densely covered by stellate trichomes ca. 0.4 mm in diam.

Type: ― COLOMBIA. Antioquia: Medellín, carretera San Cristóbal, Cerro Padre Amaya, 2800 m, 1 November 1985 (fl), C. I. Orozco, G. Lozano, P. Franco, G. Galeano 1443a (holotype COL!).

Tree (3.5–)5–10(–12) m high; branches abundantly covered with stellate trichomes, rotate and multiangular, ca. 0.4 mm in diam., with 8–18 rays; stipules triangular, 1.0– 1.5 mm long. Leaves and branches whorled, three per node, or sometimes opposite to subopposite, or occasionally alternating along the same branch; petiole (0.5–)1.0–1.5(– 3.0) cm long, adaxially grooved; blade elliptical to obovate, (4.5–)7–10(–15.5) × (3–)4.5–6.0(–9) cm, coriaceous, apex acuminate, acumen up to 0.5 cm long, sometimes obtuse to rounded, margin serrate, sometimes crenate, with glandular teeth, base obtuse-to-rounded, sometimes acute; upper side glabrescent; lower side densely covered with stellate trichomes, rotate and multiangular, 0.3–0.4 mm in diam.; domatia generally absent, sometimes small pockets enclosing hair-tufts; (0–)2–4(–5) basilaminar glandular spots on the upper side, 0–2(–3) basilaminar glandular spots on the lower side; venation acrodromous, imperfect, suprabasal, secondary veins in (4–)5–6(–8) pairs, tertiary veins percurrent, oblique. Staminate inflorescences unbranched or branched, sometimes with (sub)whorled branching, axillary or terminal, (3.5–)7–18(–36.5) cm long, solitary, peduncle 0.5–2(–6.0) cm long, central axis 0.14–0.2 cm in diam., axes densely covered with stellate trichomes, rotate and multiangular, 0.1–0.4 mm in diam.; flowers in alternate or subopposite clusters of 5–10 per node; internodes 1–5(–15) mm long; bracts of clusters widely ovate, 1–2 mm long; base sometimes with a spherical gland, ca. 0.5 mm long; pedicels 0.5–2.0 mm long, buds 1.7–2.5 mm wide, glabrous or sometimes with a tuft of trichomes at the apex; sepals 3–4, partly fused; stamens 8, connate at the base, sometimes with stellate trichomes at center of androecium, trichomes 0.3–0.5 mm long; anthers 1.2–1.8 mm long, glabrous. Pistillate inflorescences unbrached, axillary, solitary, 4.5–7.0(–10) cm long, peduncle 0.5–1.5 cm in long, densely covered with stellate trichomes, rotate and multiangular, ca. 0.4 mm in diam.; bracts widely ovate or ovate lanceolate, (2–)3–4(–5) mm long, apex acute, sometimes trilobed; flowers solitary in the axil of each bract, alternating to subopposite or whorled, pedicels 1–2 mm long; sepals 4, partly fused, lobes 2–3 mm long, apex acute; ovary 2–3 mm long, densely covered with rotate stellate trichomes, 2(–3)–locular; styles 2(–3), (3–)6–12(–14) mm long, connate at the base up to 3 mm long, generally foliose; apex entire, bipartite or serrate, sometimes obtuse to rounded, margin entire, rugose. Fruit bilobed-to-globose, 0.5–0.9 × 0.6–0.9(–11) cm; seeds 7–9 × 6 × 4.5 mm, tuberculate, brown, aril red.

Distribution: —This is an Andean species from Colombia and Peru. In Colombia, it grows in the departments of Antioquia, Cauca, Cundinamarca, Huila, Putumayo, and Risaralda and in Peru in Amazonas at elevations of (2000–)2300–2500(–2900) m. This species was seen in disturbed forest areas.

Phenology: —This species is fertile between April and November.

Etymology: —The specific epithet refers to the general occurrence of three leaves per node.

Notes: — Alchornea verticillata is characterized by leaves arranged in whorls of three, petioles of up to 3 cm in length, domatia generally absent, and the lower side of the blade densely covered with stellate trichomes of approximately 0.3–0.4 mm in diam. It is similar to A. grandiflora Müller (1865: 170) , which sometimes presents leaves arranged in whorls and has bipartite stigmas, but differs because in A grandiflora , the petioles are generally of> 3 cm in length, the domatia are two big pockets, at least at the basal pair of secondary veins, and the lower side of the blade is glabrescent, covered with trichomes approximately 0.2 mm in diam. The name A. verticillata appeared initially in the thesis of Rentería (1994), after that, it has been repeatedly used in herbaria and publications (e.g., Alzate et al. 2008). However, this name was not validly published, which is corrected here.

Additional specimens examined (paratypes): — COLOMBIA. Antioquia: Belmira, corregimiento Labores, 2650 m, A. Pérez-M. 230 ( HUA) ; Envigado, recorrido margen izquierda afluente La Miranda, quebrada La Miel, 2450–2650 m, 23 April 1996 (fl), M. Correa et al. 621 ( COL) ; Envigado, quebrada La Miel, Cerro El Higuerón, costado occidental, 2600 m, 12 December 1996 (ster), M. Correa 1616 ( HUA) ; La Estrella, cuchilla Romeral, 6º 07’60”N, 75º39’60” W, 2800 m, 23 November 1996 (fl), J. Pérez 98 ( FAUC) ; La Unión, 2500 m, July 1960 (fr), S. Espinal & E. Montenegro 167 ( COL) ; Cerro de San Miguel, 2460–2620 m, O. Marulanda 328 ( HUA) ; vía a Sonsón, 28 November 1984 (fl), C. I. Orozco et al. 1299 ( COL) ; Represa Miraflores, 2100 m, S. Espinal 4706 ( MEDEL) ; Santa Rosa de Osos, 22 km en el camino a Yarumal, 2650 m, 26 November 1988 (fl), G. McPherson 13292 ( COL, HUA). Cauca: Argelia , Cuchilla Naranjal , cuenca Guaitara (Micay), 5 August 1994 (fl), M. Beeking MB1766 ( COL) ; El Tambo, vereda La Romelia, Parque Nacional Natural Munchique, 2530 m, 23 July 1993 (ster), N. Ruíz et al. 164 ( COL) ; camino al observatorio, 2600 m, 23 July 1993 (fl), F. González et al. 2907 ( COL) ; Sendero del Oso, 2720 m, 2º 39’32” N 76º 54’ 56.1”W, 27 September 2000 (ster), O. Casañas 590 ( HUA) ; Vía santa Ana, parcela de pinos, 2700 m, 29 July 1993 (fl), G. Lozano et al. 6599 ( COL). Cundinamarca: Cabrera, vereda Peñas Blancas, 2300 m, 14 July 1988 (fl, fr), E. Linares 2530 ( COL). Huila: Algeciras, 12 km al SE, 2673 m, 23 April 1944 (fl), E. L. Little Jr. 7707 ( COL) ; San Vicente-Buenos Aires, km 13, 2700 m, 24 April 1944 (fl); E. L. Little Jr. 7709 ( COL) ; La Plata, Finca Meremberg, 2450 m, 2 October 1984 (fl), G. Lozano et al. 4446 ( COL). Risaralda: Pereira, Parque Regional Ucumarí, vereda La Pastora, 2100 - 2400 m, 15 June 1989 (fl), R. Bernal et al. 1698 ( COL) ; Santuario, vereda Las Colonias, 2910 m, 2 February 1983 (ster), J. H. Torres et al. 1483 ( COL) ; Margen derecho del río San Rafael, 2500 m, 25 February 1983 (ster), J. H. Torres et al. 2271 ( COL). Putumayo: Mocoa, corregimiento El Pepino, carretera vía El Pepino-Sibundoy, cerca al “Mirador”, 2000 m, 3–4 May 1994 (ster), P. Franco 5530 ( COL) ; San Francisco, vereda Minchoy, Bentura Montenegro, 1º11’22.3”N 76º50’10.7”W, 2442 m, 14 October 2016 (ster), M. Salazar 757 ( COL) ; Santiago, vereda Santa Clara – Alto Fusanoy, vía antigua El Encano-Santiago, 2900 m, 1 July 2003 (fl, fr), J. Benavides & S. Franco 3415 ( COL) ; Santiago, vereda El Eden, sector Garganta de Balsayaco, 2340 m, 22 September 2016 (fl), J. Murillo 4806 ( COL) . PERU. Amazonas: Bongará, laguna de Pomacochas, 2550 m, 27 March 1998 (fr), H. van der Werff et al. 15812 ( USM) ; Chachapoyas, road from Chachapoyas to Mendoza, 6º12’37” S 77º42’57”W, 2200 m, 20 October 2000 (fl), M. Weigend et al. 2000/894 ( MSB, USM) .

Figures

FIGURE 3. Alchornea tenuinervia J.Murillo. A. Staminate branch (D. Soejarto 4118, COL). B. Pistillate branch (W.R. Philipson 2315, COL). Morphological variation of the blade C. W.R Philipson 2284 (COL). D. D. Tuberquia 1325 (COL). E. J. Idrobo 1303 (COL).

FIGURE 4. Alchornea verticillata P.Franco & Rentería ex J.Murillo. A. Staminate branch (C. Orozco 1443a, COL). B. Pistillate branch (J. Benavides 3415, COL). C. Detail of the leaf underside (C. Orozco 1443a, COL).