26. Monstera integrifolia Zuluaga & Croat, Phytotaxa 334(1): 6. 2018. (Figs. 46, 47)

Type: — PANAMA. Chiriquí: Distrito Gualaca, corregimiento Hornito, Reserva Forestal Fortuna, trails near Chiriquí Research Center Jorge L. Arauz, 1200–1500 m elevation, 31 Jan 2013, A. Zuluaga 916 (holotype WIS, isotypes PMA!, MO!) .

Nomadic vine, appressed-climbing. SEEDLINGS: bearing foliage leaves. JUVENILE PLANTS: root climbers; stems dark green with white dots, cylindrical; internodes 2–8 cm long, 4–10 mm diam.; petiole distinct, dark green with white dots, smooth, 8–10 cm long, sheathed to base of the geniculum; petiole sheath deciduous or slightly persistent; blades lanceolate, truncate at base, acuminate at apex, 8–14 × 5–8 cm; not appressed to the phorophyte; collective veins visible; fenestrations absent.ADULT PLANTS: root climbers; stems dark green or yellowish, sometimes white-spotted, cylindrical; internodes 2–4 cm long, 1.4–2.0 cm diam., 1.4–2.0 times longer than wide; anchor roots and feeder roots dark brown; petioles dark green, whitish or with white dots, smooth, 10–30 cm long, sheathed to base of the geniculum; petiole sheath slightly persistent or deciduous with fibrous fragments; geniculum smooth with white dots, sulcate adaxially, convex abaxially, 1–3 cm long; blades lanceolate, cuneate or attenuate at base, acuminate at apex, coriaceous, 30–40 × 9–13 cm, 2.0–2.6(3.3) times longer than wide, slightly decurrent on geniculum, decurrent portion 1–2 mm wide, drying black with light brown dots; midrib ribbed adaxially, convex abaxially, primary lateral veins 5–10 per side, slightly sunken adaxially, prominent abaxially, departing midrib at 35–45°; secondary veins parallel across primary lateral veins, reticulate towards the margins; collective veins slightly visible; fenestrations absent or present, generally the fenestrations break at the margin; margins pinnatilobed with 2–3 lobes per side. INFLORESCENCES on ascending stems, arranged in the axils of the leaves; peduncle smooth, 6–15 cm long, 0.6– 1.2 cm diam.; spathe acuminate, light green during development, white to cream internally and green externally at anthesis, 15–18 × 8–9 cm, up to 8 cm longer than the spadix; spadix white (both during development and at anthesis), 8–10 cm long, 1.7–2.0 cm diam., 0.6–0.9 times as long as peduncle; basal sterile flowers 4–5 mm long; fertile flowers 4–5 mm long; stamens 2–4 mm long, with laminar filaments; anthers 1.5–2.0 mm long; ovary rectangular in longitudinal section, ribbed, 2–4 × 2–3 mm; style hexagonal, 2–4 × 3–4 mm; stigmatophore conical, 0.5–1.0 mm long; stigma circular with a yellowish stigmatic secretion; berries with a white stylar cap during development, mature stylar cap unknown; pulp unknown; seeds unknown.

Distribution and ecology: — Monstera integrifolia ranges from northern Costa Rica to western Panama at 1000– 2000 m, in Tropical wet forest or Premontane rain forest life zones.

Phenology: —Flowering has been recorded in November. Fruiting in December.

Discussion: —The species is a member of sect. Monstera . It is distinguished by having narrow leaf blades with primary lateral veins that arise from the midrib at an angle of 35°, whitish and mottled petioles, with a petiolar sheath that disintegrates as fibrous residues, and flowers with a conical stigmatophore. It could be confused with Monstera anomala and M. standleyana . Monstera anomala never has fenestrate leaf blades and the flowers have an elongated style with a constriction in the middle. M. standleyana plants are usually more robust, have a columnar stigmatophore, and inhabit lower elevations (0‒1360 m).

Monstera integrifolia is most similar to M. xanthospatha, a species endemic to the West and Central Cordilleras of Colombia at elevations between 1500–2300 m. Both species are small plants, flowering when they are less than 10 m tall, and inhabit montane cloud forests. Monstera integrifolia differs from M. xanthospatha in having shorter petioles and peduncules (9–14 vs. 13–25 cm), a longer spadix (8–10 vs. 5–7 cm), and flowers with raised styles (vs. flat).

Additional specimens examined: — COSTA RICA. Cartago: Turrialba, Chirripo, Moravia de Chirripó, Bosque nuboso, 1602 m, 20 December 2019, (Fr.), M. Cedeño et al. 638 (USJ!) ; Turrialba, Chirripo, Moravia de Chirripó, Bosque nuboso, 1602 m, 20 December 2018, (Fr.), M. Cedeño et al.1639 (USJ!) ; Turrialba, Chirripó, Tayutic, Jicotea, Siguiendo la Fila Vereh, entre la Cueva del Sapo y Fila Vereh, 1634 m, 22 December 2018, (Fl., Fr.), G. Herrera 8005 (CR!, MO!) ; Heredia: Sarapiqui, La Virgen, Primary forest along Rio San Rafael, Atlantic slope of Volcan Barva, 1500 m, 12 April 2019, (Fr.), M.H. Grayum 7017 (MO!) . PANAMA. Bocas del Toro: Prov. Cerro Colorado, 9.2 miles W of Chamé; along trail E of road which leads down to stream, 08°35’N 081°50’W, 1450–1480 m, 06 July 1988, T.B. Croat 69067 (MO!, PMA!) ; Chiriquí: Fortuna Dam site, 08°44’N 082°15’W, 1400–1600 m, 15 September 1977, J. Folsom et al. 5598 (MO!) ; Ridges and summit of Cerro Hornito, above Los Planes de Hornito. Elfin forest, 08°42’N 082°06’W, 2100 m, 14 March 1982, S. Knapp et al. 4220 (MO!) ; Cerro Hornito, S facing slope approached from Los Planes de Hornito, 08°41’N 082°10’W, 1750–1900 m, 22 September 1987, T.B. Croat 67978 (MO!) ; Along road to Fortuna dam site on Río Chiriquí, N of Gualaca, 7.7 mi beyond Francisco Linare’s lane, 19.2 mi beyond bridge over the Río Estí; 9.1 mi beyond Los Planes de Hornito; 8 mi beyond jct. in road to tunnel, 08°42’N 082°14’W, 1300 m, 27 Nov 1979, T.B. Croat 48742 (MO!) ; Fortuna Dam Area, Fortuna-Chiriquí Grande, 5.3 miles N of center of Fortuna Dam, then 1.4 miles W along gravel road to Continental Divide Trail, 08°44’N 082°17’W, 23 June 1994, T.B. Croat & G. Hua 76344 (MO!) ; Gualaca. Corregimiento Hornito, Reserva Forestal Fortuna, senderos cerca al centro de investigaciones Jorge L. Arauz, 08°47’N 082°13’W, 1200–1500 m, 31 enero 2013, A. Zuluaga 916 (PMA!) ; Panamá: Capira. Cerro Campana, along trail to summit, 08°41’27”N 079°55’02”W, 780–875 m, 20 July 1974, T.B. Croat 25194 (MO!) .