Monstera membranacea Madison, Contr. Gray Herb.

Croat, Thomas B., Cedeño-Fonseca, Marco & Ortiz, Orlando O., 2024, Revision of Monstera (Araceae: Monsteroideae) of Central America, Phytotaxa 656 (1), pp. 1-197 : 113-116

32. Monstera membranacea Madison, Contr. Gray Herb. 207: 55. 1977. ( Figs. 53 , 54 )

Type: — COSTA RICA. Prov. San José: [Puriscal], western slope of Cerro Tufares , 800 m, 2 October 1972, M. Madison 738 (holotype GH! [2 sheets], isotypes CR!, MO!) .

Nomadic vine, appressed-climbing habit. SEEDLINGS: bearing foliage leaves. JUVENILE PLANTS: root climbers; stems dark green, smooth, cylindrical; internodes 3–8 cm long, 2–4 mm diam.; petiole distinct, light green, smooth, 3–6 cm long, sheathed up to half its length, petiole sheath persistent; blades ovate, cordate at base, acuminate at apex, membranous, 7–10 × 3–6 cm, not appressed to the phorophyte; fenestrations absent. ADULT PLANTS: root climbers; stems bright green, glossy, smooth, cylindrical; internodes 1–3 cm long, 1.0– 2.5 cm diam., 1.0–1.2 times longer than wide; cataphylls with a very reduced blade, light green, deciduous; anchor roots black; feeder roots light brown; petiole light green, smooth, 25–60 cm long, sheathed up to the medial part or 5–7 cm before base of the geniculum; petiole sheath persistent; unsheathed portion terete; geniculum smooth, slightly terete, 1.0– 2.5 cm long; blades ovate or elliptic, subcordate to cordate at base, obtuse at apex, membranous, drying greenish, yellowish, grayish or blackish, 18–55 × 15–30 cm, 1.1–1.8 times longer than wide, decurrent on geniculum, decurrent portion 1–2 mm wide; midrib ribbed adaxially, convex abaxially, drying reddish, blackish or yellowish on both surfaces; primary lateral veins 8–12 per side, bifurcated or trifurcated, markedly reticulated towards the margin, strongly sunken adaxially, prominent abaxially, departing midrib at 65–70°, drying yellowish, blackish; secondary veins reticulate; collective veins not visible; fenestrations absent or present, arranged in a single series near the midrib, on one or both sides; margins entire or pinnatilobed, 4–10 lobes per side. INFLORESCENCES on ascending stems, 1–5 simultaneously at flowering time, arranged in the axils of the leaves or subtended by cataphylls; peduncle smooth, 9–20 cm long, spathe long-acuminate, light green during development, yellowish-green externally and cream internally at anthesis, coriaceous, open in the medial part, closed at base and apex, deciduous as fragments post-anthesis, 10–17 × 5–9 cm, up to 5 cm longer than spadix; spadix white during development, cream at anthesis, 7–11 cm long, 1.0– 3.5 cm diam., 5.4–5 times longer than wide; basal sterile flowers 4–5 mm long, with a yellowish stigmatic secretion; fertile flowers 5–7 mm long; stamens 1–2 mm long, with laminar filaments; anthers 1.5–2.0 mm long; ovary square in longitudinal section, ribbed, 2–3 × 3–4 mm; style compressed and hexagonal, 2–3 × 3.5–4.0 mm; stigmatophore slightly cupuliform, at base slightly cleft on the style; stigma circular, with a yellowish stigmatic secretion; berries with a yellowish-green stylar cap during development, mature stylar cap yellow; pulp orange; seeds globose, green with reddish dots, 4–7 mm long.

Distribution and ecology: — Monstera membranacea ranges from Costa Rica (Caribbean south and Central Pacific to south) to Panamá (Chirquí), at 0–800 m, in Tropical wet forest life zones.

Phenology: —Flowering has been recorded in November, and fruiting from March to July.

Discussion: —The species is a member of sect. Monstera . It differs from the other species of the section by its light green petiole sheathed to half of its length with persistent wings, the bright green, distinctly membranous leaf blade, the spathe yellow externally and cream internally, with its margins overlapping at the base and apex (open only in the middle), and its infructescence with the stylar layer yellow green and the fruits with orange pulp. In the pre-adult state, Monstera membranacea can be confused with M. filamentosa , but the latter has brown petioles, sheathed to the base of the geniculum and with the wings of the sheath deciduous.

Additional specimens examined: — COSTA RICA. Limón: Talamanca, Between Bri Bri and Sixaola , 20–70 m, 5 July 1983, (Fl.), K. Barringer 3500 ( MO!) ; Talamanca, Bríbri, R.V.S.M. Manzanillo , 20 m, 3 March 2018, (Fr.), M. Cedeño & M. Jiménez 1332 ( USJ!) ; Talamanca, Telire, Camino a Sibody , 130 m, 30 Abril 2017, (Fr.), M. Cedeño et al. 1088 ( USJ!) ; Talamanca, Cahuita, Bosques de Manzanillo , 50 m, 9 January 2017, (Fl., Fr.), M. Cedeño et al. 1106 ( USJ!) ; Puntarenas: Slopes above airport , disturbed priamary forest, Rincón, 150 m, 11 February 1974, (Fr.), R. Liesner 2061 ( CR!, MO!) ; P.N. Carara , Estación Quebrada Bonita, 30 m, 29 September 1983, (Fr.), I. Chacón 1408 ( CR!) ; Garabito, Tárcoles, P.N. Carara. Estación Quebrada Bonita, Bosque primario, 50 m, 27 July 1990, (Fl.), E. Bello 2379 ( CR!, MO!) ; Golfito, Puerto Jiménez , P.N. Corcovado, Lower Lookout Trail, 25 m, 31 July 1988, (Fr.), C. Kernan 744 ( CR!) ; Osa, Sierpe , 50 m, 24 March 1973, (Fr.), W. Burger & J. Gentry 8865 ( CR!, MO!) ; Golfito, Jiménez, Sector Los Patos , colecta en bosque a orilla del río Rincón, 70 m, 17 May 2000, (Fl.), L. Acosta 1248 ( CR!, MO!) ; Golfito, Jiménez, Sector Los Patos , colecta en bosque a orilla del río Rincón, 70 m, 17 Mayo 2000, (Fr.), L. Acosta 1252 ( CR!) ; Golfito, Jiménez, In low, flat forest from Rio Sirena to Rio Pavo, 25 m, 2 April 1988, (Fl., Fr.), B.E. Hammel 16638 ( CR!, MO!) ; Golfito, Jiménez, La Palma , Rio Rincon aguas arriba, camino a Cerro de Oro, 100 m, 30 July 1990, (Fr.), G. Herrera 4062 ( CR!, MO!) ; Golfito, Jiménez, Sirena , Pavo Trail to old airstrip, 1 m, 21 June 1989, (Fr.), C. Kernan 1173 ( CR!) ; Osa, Moist forest in valley-bottoms , 50–200 m, 1 September 1970, (Fr.), W. Burger 7212 ( MO!) ; Along highway to Golfito from Panamerican Hwy. at Río Claro , 60 m, 14 September 1987, (Infer.), T.B. Croat 67592 ( MO!) ; Forest at eastern base of Fila Barriganes . Ca. 1 km S and 3 km W of Clañasas, 60 m, 4 March 1985, (Infer.), T.B. Croat 59821A ( MO!) ; Lowland Forest between guard station and Quebrada Bonita , 40 m m, 25 July 1985, (Fl.), M.H. Grayum 5706 ( MO!) ; Osa, Corcovado National Park , Primary forest on hills 0 km to 1 km W of the park headquarters at Sirena, 0–200 m m, 4 July 1977, (Fl., Fr.), R. Liesner 2828 ( MO!) ; San José. Acosta, Sabanillas, Acosta, Las Vegas , Rio Parritilla, camino a Alto Pitales, 200 m, 3 May 1997, (Fr.), J. Morales 6179 ( CR!, MO!) ; Puriscal, Chires, Camino viejo a Quepos, A orillas del camino, 700 m, 21 May 2005, (Fr.), D. Santamaría 2052 ( CR!) . PANAMA. Chiriquí: Burica Peninsula, 8 mi west of Puerto Armuelles, 08°17’N 082°56’W, 200 m, 02 March 1973, T.B. Croat 22494 ( MO!) ; Panamá: Le Clezio , Jan 1969, N. Bristan 69 ( MO!) .

Figures

FIGURE 53. Monstera membranacea from Manzanillo, Costa Rica. (A) Developing inflorescence. (B) Inflorescence with open spathe, front and back views. (C) Mature infructescence, stylar plates detaching. (D) Fertile flower; in lateral view (left), and in longitudinal section (right). (E) Stylar plate with stigma (left) and one stamen (right). (F) Sterile flower; lateral view (left), and longitudinal section (right). (G) Adult plant. (H) Juvenile plant. (I) Seeds. M. Cedeño et al. 1532 (USJ). Image from Cedeño-Fonseca et al. (2022).

FIGURE 54. Monstera membranacea. Adult plant growing 2 m above the ground in Golfito, Costa Rica. (Not collected). Photo by M. Cedeño-Fonseca.