Philodendron tenue K. Koch & Augustin

Ortiz, Orlando Oriel, de Stapf, María Sánchez, Baldini, Riccardo Maria & Croat, Thomas Bernard, 2019, Synopsis of aroids (Alismatales, Araceae) from Cerro Pirre (Darién Province, Panama), Check List 15 (4), pp. 651-689 : 683

Philodendron tenue K. Koch & Augustin ( Fig. 7F)

Material examined. Middle slopes on W side of Cerro Pirre; 07°57′N, 077°46′W; 550–760 m; 28 Jun. 1988; T. B. Croat 68871 ( MO). Ibid.; 07°56′N, 077°45′W; 800–1050 m; 29 Jun. 1988; T. B. Croat 68954 ( MO). Parque Nacio- nal Darién, vicinity of Cerro Pirre base camp, along trail near E side of Río Paracida; 08°00′N, 077°48′W; 0–80 m; 1 Jul. 1988; T. B. Croat 68998 ( MO). Cerro Pirre, vicinity of station along Río Perisenico; 08°01′N, 077°44′W; 110 m; 26 Jul. 1994; T. B. Croat 77107 ( MO). Ibid., valley between between Pirre and next most southernly peak, sloping hillside; 07°40′N, 077°42′W; 1250– 1300 m; 10–20 Jul. 1977; J. P. Folsom 4417 ( MO). Ibid., campamento cerca del segundo mirador; 07°59′49″N, 077°42′43″W; 610 m; 2 Dec. 2016; O. O. Ortiz 2713 ( PMA).

Identification. This species is characterized by having short internodes, persistent fibrous cataphylls, more or less terete petioles (equal or longer than the blade), ovate to ovate-triangular blades with V-shaped sinus, nonnaked posterior ribs, and numerous primary lateral veins (eight to 20 per side). In the field, this species can be vegetatively confused with P. edenudatum Croat , but the latter differs in having intact cataphylls and blades with three to four pairs of basal veins and five to six primary lateral veins per side.

Distribution and ecology. Colombia, Costa Rica, Ecuador, Honduras, Nicaragua, Panama, and Venezuela. Philodendron tenue ocurrs along the elevation gradient of Cerro Pirre. The collections made indicate that this species can grow in semideciduous, evergreen, submontane and montane forests, at 80–1300 m.