Alchornea conceveiboides J.Murillo, 2018

Murillo-Aldana, José, 2018, Novelties in the genus Alchornea (Euphorbiaceae), Phytotaxa 375 (3), pp. 203-213 : 206-207

Alchornea conceveiboides J.Murillo , sp. nov. ( Fig. 2 )

Alchornea conceveiboides has leaves similar to those of some Conceveiba species, such as C. pleiostemona by the venation and to C. martiana by the shape of leaves. It is characterized by widely cordate leaves, abundant minute papillae on the lower surface of the blade, and pistillate flowers with free sepals.

Type: ― COLOMBIA. Antioquia: Anorí, corrg. Providencia, valle del río Anorí, entre Dos Bocas y Anorí, 400–700 m, 26 April–3 May 1973 (fl), D.D. Soejarto, J. L. Zarucchi, E. Renteria & R. Wagner 3936 (holotype COL!, isotype HUA!).

Tree (8–) 15–20 m high, abundantly covered with multiangular stellate trichomes, these ca. 0.2 mm in diam. Leaves alternate; stipules triangular, 3–4 mm long; petiole (6–)8–11(–18) cm long, terete, striate; blade elliptical to broadly elliptical, (12–)18–24(–33) × (14–)17–24 (–29) cm, apex acuminate, acumen (0.2–)0.5–1.0 cm long, sometimes obtuse, margin crenate, with glandular teeth, base cordate, upper surface glabrescent, lower surface covered with rotate stellate and multiangular stellate trichomes of similar size, densely covered with minute papillae; basilaminar glandular spots 2–4, laminar spots sometimes numerous, pocket domatia; venation acrodromous, suprabasal, imperfect, pinnate semicraspedodromous toward the apex, 7–10 pairs of secondary veins, tertiary venation percurrent, oblique. Inflorescence branched, axillary. Staminate inflorescence 12–17 cm long, peduncle 0.8–1.5 cm long, axis 0.1–0.2 cm diam., occasionally with a pistillate flower at the apex of a branch; flowers in clusters of up to 10 per node, internodes 2–6 mm long, bracts of clusters triangular, 1 × 1.8 mm, with a spherical gland on each side of the base, flowers with pedicels ca. 1 mm long, buds ca. 2 mm wide, pedicel and base of bud covered with abundant multiangular stellate trichomes, sparsely pubescent with simple or multiangular stellate trichomes toward the apex; calyx not seen in anthesis, stamens 8, connate at the base, glabrous, anthers ca. 1 mm long. Pistillate inflorescence 11–20 cm long, with sparse branching primarily toward the base; flowers in clusters of 3–4 per node, sessile, bracts widely ovate, 1.5 × 2 mm, apex obtuse, spherical gland on each side of the base; sepals (3–)4, free, 1.0– 1.5 mm long; ovary ca. 1.5 mm long, 2-locular, styles 2, 0.5–0.6 cm long, connate at the base for <0.5 mm, foliose, apex entire, margin smooth, stigma papillate. Fruit bilobed, 0.7 × 0.6 × 0.4–0.5 cm, green, densely covered with stellate trichomes, styles persistent; seeds elliptical, 0.5–0.55 × 0.45 × 0.4–0.45 cm, tuberculate, brown, aril bright red.

Distribution: —This species has been collected in the departments of Antioquia, Choco, Nariño, and Risaralda at elevations of <1550 m. Vegetation studies show this taxon to be a characteristic element of some wetland forests in the low areas in western Nariño (del Valle 2000).

Phenology: —Staminate flowers have been found in June and December, with pistillate flowers in May and fruits in May and December.

Common name: —Balsamacho (del Valle 2000, Nariño).

Etymology: —This specific epithet refers to the similarity of the leaves to those of some species of Conceveiba Aublet (1775: 923) .

Notes: —This species is characterized by widely cordate leaves, abundant minute papillae on the lower surface of the blade, and pistillate flowers with free sepals. None of these characters is common in Alchornea . Papillae are only present in A. conceveiboides . Cordate leaves are present in A. brittonii Secco (2004: 95) , A. grandis Bentham (1846: 164) , and A. latifolia Swartz (1788: 98) . Free sepals are found in A. acroneura , frequently in A. castaneifolia (Humb. & Bonpl. ex Willdenow 1805: 809) Jussieu (1824: 42) and sometimes in A. glandulosa Poeppig (1841: 18) and A. discolor Poeppig (1841: 18) . The leaves are very similar to those of Conceveiba pleiostemona Smith (1912: 243) , particularly with regard to the venation; the species is also similar to Conceveiba martiana Baillon (1865: 221) with respect to the shape of the blade and numerous papillae on the lower surface; thus, misidentifications with Conceveiba have occasionally occurred. In various herbaria, this species has also been confused with Alchornea leptogyna Diels (1937: 103) , a species described from Ecuador and which according to Secco (2004) could be considered synonymous with A. glandulosa . In agreement with the original description ( Diels 1937), A. leptogyna differs from A. conceveiboides with regard to the size of the blade (10–20 cm vs. 18–30 cm), the base of the blade (narrowed vs. cordate), the apex of the blade (acumen of 2 cm vs. <1 cm), and the structure of pistillate inflorescence (unbranched vs. branched).

Additional specimens examined (paratypes): — COLOMBIA. Antioquia: Anorí, Planta eléctrica de Provincia , camino a Aljibes , 7º19´61”N, 75º02´407”W, 350 m, 26 March 1996 (fl), R. Fonnegra et al. 5944 ( HUA) ; Vereda Puerto Rico , 7 ° 8´20”N, 75 ° 08´20”W, 12 November 1999 (ster), D. Tuberquia 1447 ( JAUM) ; Corregimiento Providencia, valle del río Anorí, entre Dos Bocas y Anorí, 26 km S & 23 km W (air) of Zaragoza (7 ° 13´N, 75 ° 03´W), 400–700 m, 31 May 1976 (fr), J. Shepherd 316 ( COL, HUA) ; Frontino, Parque Nacional Natural Las Orquídeas, vereda Venados , 660 m, June 1988 (fl), A. López & H. Triana 68 ( COL) ; Urrao, vereda Venados, sector Venados Abajo , Parque Natural Las Orquídeas 1150 m, 10 November 2010 (ster), A. Castaño 1033 ( JAUM) ; Yarumal, Corregimiento El Cedro, sector Alto de La Tolda , 7 ° 10´N, 75 ° 30´W, 1300 m, 17 December 1990 (ster), J. Ramírez 3940 ( JAUM). Chocó: Tadó, 5 ° 16´10”N, 76 ° 73´10”W, 80–140 m, December 2003 – January 2004 (ster), D. Botero 436 ( JAUM). Nariño: Olaya Herrea, vereda Barrio Caliente, río Satinga , 2 ° 21´N, 78 ° 22´W, 0–5 m, 17 December 1992 (fl, fr), R. Caballero & L. Toro 70 ( COL, MEDEL) ; Vereda Naidizales, 20–30 m, 14 March 1991 (ster), R. Carmona 172 ( COL, MEDEL). Risaralda: Mistrató, entre los corregimientos de Geguadas y Puerto de Oro , 1550 m, 29 March 1992 (ster), J. L. Fernández et al. 9581 ( COL, HUA) .

Figures

FIGURE 2. Alchornea conceveiboides J.Murillo. A. Staminate branch (R. Caballero 70, COL). B. Pistillate inflorescence (D. Soejarto 3936, COL). C. Pstillate flowers (D. Soejarto 3936, COL).