Syngonium yurimaguense Engler, Bot. Jahrb. Syst. 38: 141. (1905).
Hemiepiphytic vine; stem 1–1.5 cm diam., the epidermis becoming brown, fl flaking; petioles slender, sheathed to upper 2/3, about as long as or to 3 times longer than the blade, 24–36 cm long, the sheath briefly free-ending and acute, the unsheathed portion acute adaxially; blades thin, trisect, the leaflets conspicuously free; median leaflet ovate-elliptic to oblong-elliptic, bluntly acute to gradually acuminate at the apex, obtuse to acute and attenuate at the base, 11–23 cm long, 4.5–9 cm wide; primary lateral veins 4–7 pairs, at least part of them departing the midrib at 90 degree angle, then arcuate or almost straight to the collective vein; tertiary veins distinct; primary collective vein distinct, 2–6 mm from the margin, generally more or less straight; lateral leaflets generally somewhat narrower, acuminate or narrowly acute on the inner margin at the base, hastate lobed on the outer margin, the auricles 2–5 cm long, acute to narrowly rounded at the apex. Inflorescences 1–2 per axil, the prophylls slender; peduncles cat 6.5 cm long at anthesis, less than 3 mm diam. (dried); spathe 9–10 cm long; spathe tube oblong-elliptic, 3–3.5 cm long, cat 1.5 cm diam., probably green; spathe blade oblong-elliptic, acuminate at the apex, white (fide Engler, 1877), pistillate portion of the spadix 2 cm long, I cm diam. (dried), the pistils depressed-globose; staminate portion of the spadix clavate, cat 5 cm long, 7 mm diam. (dried), the sterile flowers irregular, 1–1.5 mm diam., broadest in the direction of the axis, the fertile flowers irregularly 4–5-sided, completely fused into a synandrium with no sign of fusion, the apex truncate, margin irregularly scalloped. Infructescences creamy yellow, subglobose, 5.5 cm long, 4.5 cm diam.; peduncle to 2 cm long; seeds black, 4–5 mm long.
Type: Peru, Loreto, Yurimaguas, Ule 9237 (B. holotype; K, isotype).
Sucumbios: Along road between Lago Agrio (Nueva Loja) and Coca (Pto. Francisco de Orellana); 26 km S of Lago Agrio, 4.6 km S of El Emo, then 2.8 km W of main Lago Agrio-Coca Road, along farm road, 355 m, 0°5'S, 76°54'W, Croat 72525 (MO). Napo: Along Cepe Ferry road (east of Lago Agrio) 8.8 km S of Río Aguarico on road to Coca (San Francisco de Orellana), 280 m, 0°5'N, 76°50'W, Croat 58516 (MO, QCA); along road between Tena and Puyo, 61.5 km N of Puyo, Croat 49660 (MO); Estacion Biologica Jatun Sacha, along S bank of Río Napo, 8 km E of Puerto Misahualií, 450 m, 1°4'S, 77°36'W, Croat 73402 (MO); Cerón 735 (MO); Cerón 1387 (MO); Balslev & Dea 2891 (QCA); Añangu, S bank of Río Napo, 95 km downstream from Coca, 300 m, 0°32'S, 76°23'W, Balslev et al. 62306 (AAU); along road between Tena and Puyo, 61.5 km N of Puyo, 500 m, Croat 49660 (MO); Reserva de Producción Faunística Cuyabeno, north of Laguna Grande, 265 m, 0°00'00"S' 76°12'W, Poulsen 79414 (AAU); Nielsen 76008 (AAU). Pastaza: Pozo petrolero "Ramirez". 20 km al sur de la población de Curaray, 300 m, 1°32'S, 76°51'W, Zak & Espinoza 5241 (MO, QCNE); Puyo, Comunidad Santa Cecilia,380 m, 1°30'S, 77°27'W, Palacios 10098 (MO, QCNE). Morona-Santiago: Los alrededores del Centro Tuutin Entsa, 330 m, Anananch RBAE 202 (MO). – Brazil, Peru, Bolivia. at elevations of 50--700 m.