Monstera molinae Grayum, Phytologia, 1997

Croat, Thomas B., Cedeño-Fonseca, Marco & Ortiz, Orlando O., 2024, Revision of Monstera (Araceae: Monsteroideae) of Central America, Phytotaxa 656 (1), pp. 1-197 : 119

35. Monstera molinae Grayum, Phytologia 82: 48. 1997. ( Figs. 56 , 57 )

Type: — COSTA RICA. Guanacaste: Parque Nacional Rincón de la Vieja, the SE slopes of Volcán Santa María, above Estación Hacienda Santa María , 900–1200 m, 27–28 January 1983, G. Davidse, L.D. Gómez, M. Sousa, C.J. Humphries, N. Garwood, R. Hampshire & M. Gibby 23344 (holotype CR!, isotype MO!) .

Nomadic vine, appressed-climbing and pendent habit. SEEDLINGS: filiform. JUVENILE PLANTS: root climbers; stems dark green, smooth, cylindrical; internodes 4–6 cm long, 3–5 mm diam.; petiole distinct, dark green, smooth, 6–10 cm long, sheathed to base of the geniculum; petiole sheath persistent; blades obovate, subcordate to truncated at base, acuminate at apex, coriaceous, 7–10 × 5–8 cm, slightly appressed to the phorophyte; fenestrations absent. ADULT PLANTS: root climbers with free lateral branches; stems beige to light brown, smooth, cylindrical or dorsoventrally compressed and slightly sulcate; internodes 2–14 cm long, 0.5–0.6 cm diam., 4–23 times longer than wide; anchor roots whitish; feeder roots dark brown; petiole light green, smooth, 10–25 cm long, sheathing to base of the geniculum or base of the leaf blade; petiole sheath persistent or semi-persistent; geniculum smooth, sunken adaxially, convex abaxially, 6–15 mm long; blades ovate, oblique, cordate to subcordate or obtuse at base, acuminate at apex, coriaceous, drying reddish with black or brownish dots, 10–30 × 11–25 cm, 1.0–1.4 times longer than wide, decurrent on the geniculum, decurrent portion 1–2 mm wide; midrib ribbed adaxially, convex abaxially, drying dark or reddish brown on both surfaces, primary lateral veins 7–10 per side (occasionally 2 of them can emerge at once and then spread to the margin), strongly sunken adaxially, prominent abaxially, departing midrib at 75–80°, drying black up to the medial part; secondary veins prominent, reticulate towards the margin; collective veins not visible; fenestrations absent; margins entire or pinnatilobed with 2–4 lobes per side. INFLORESCENCES on free lateral shoots and ascending stems, 1–5 simultaneously at flowering time, arranged in the axils of the leaves; peduncle smooth, 4–5 cm long; spathe obtuse to short acuminate, light green during development, yellowish green externally and white internally at anthesis, completely open at apex, deciduous post-anthesis (tearing in several parts), 8–12 × 5–9 cm, up to 1 cm longer than the spadix; spadix white during development, cream at anthesis, 7–15 cm long, 2–3 cm diam., 3.2–3.4 times longer than wide; basal sterile flowers 4–5 mm long, with an orange stigmatic secretion; fertile flowers 4–7 mm long; stamens 1–2 mm long, with laminar filaments; anthers 1–3 mm long, the filaments do not exceed the styles at anthesis; the flowers on the spadix are separated, allowing exposure of the thecae; ovary square in longitudinal section, ribbed, more slender than style, 2–4 × 2–3 mm; style square, cylindrical or hexagonal, 3–5 × 3–4 mm; stigma linear, cleft on style, black at anthesis; berries with a creamy stylar cap during development, mature stylar cap moss-green; pulp grayish; seeds light-brown with pale dots, elongated, 5–10 mm long.

Distribution and ecology: — Monstera moliniae is endemic to Costa Rica (Atlantic slope and near Continental Divide, Cordilleras de Guanacaste, Tilarán and Central), from sea level to more than 1200 m, in Tropical wet forest and Tropical wet forest transition to Premontane wet forest life zones.

Phenology: —Flowering has been recorded in January to March, May, and November, and fruiting in June and December.

Discussion: —The species is a member of sect. Marcgraviopsis characterized by its hemiepiphytic vine-like habit, petioles sheathed to near base of blade with a deciduous sheath, broadly ovate to elliptical blades which are broadly cuneate to rounded or truncate at base, deeply pinnatifid with 2–5 pinnae on at least one side and lacking perforations, 4–8 primary lateral veins per side, peduncles shorter than spadix with the spathe green to olive-green outside, creamy white within.

Monstera molinae is most easily confused with M. spruceana which differs in being appressed-climbing with the petioles more than 20 cm long and the blades generally more than 30 cm long as well as by the larger spadices which are 11 to 18 cm long at anthesis. In contrast M. molinae has a more scandent habit, petioles less than 20 cm long, blades less than 30 cm long and the spadices about 5–11 cm long.

The populations of Monstera molinae are distributed only in the Caribbean slope and are located mainly in primary forests. Adult plants develop hanging reproductive stems. In La Tirimbina Biological Station, the reproductive hanging stems reach the ground, eventually becoming creepers ( Cedeño-Fonseca et al. 2022).

Additional specimens examined: — COSTA RICA. Alajuela: Upala, Aguas Claras, Cuenca del Pizote , 800 m, 4 March 1999, (Infer.), G. Herrera 1517 ( CR!, MO!) ; Upala, Dos Ríos, P.N. Guanacaste, Cordillera de Guanacaste, Estación San Ramón, Dos Ríos , Límite del parque a 2 km de la casa, 550 m, 27 January 1995, (Fr.), F. Quesada 191 ( CR!, MO!) ; Camino entre la estación de la Reserva Forestal de San Ramón y el camino a la colonia Palmareña , 1 February 1987, (Fr.), G. Herrera 499 ( MO!) ; Along road between Cañas and Upala , 400 m, 24 June 1976, (Infer.), T.B. Croat 36259 ( MO!) ; San Carlos, Llanura de San Carlos , 100 m, 21 February 1966, (Fr.), A. Molina 17685 ( MO!) ; Remnant evergreen forest and secondary growth in the tropical-premontane wet forest transition zone about 3 km NNE of Bijagua along the new road to Upala , 450 m, 7 November 1975, (Fl., Fr.), W. Burger 9882 ( CR!) ; Upala, Aguas Claras, Sendero Cabinas Bromelia , 600 m, 15 Diciembre 2016, (Fr.), M. Cedeño et al. 983 ( USJ!) ; Guanacaste: Liberia, Mayorga, Estacion Cacao , Sendero casa de Fran, 1000 m, 9 February 1995, (Fr.), E. Fletes 52 ( CR!) ; La Cruz, Santa Cecilia, Estacion Pitilla 9 km, S. de Santa Cecilia, 700 m, 14 July 1997, (Fr.), C. Moraga 910 ( CR!, MO!) ; Parque Nacional Rincón de la Vieja, 900–1200 m, 27 Enero 1983, (Fr.), G. Davidse 23344 ( MO!) ; Rincón de la Vieja National Park , 800 m, 28 January 1983, (Fr.), N. Garwood 755 ( CR!, MO!) ; El Dos de Tilaran , 1000 m, 12 April 1986, (Fr.), W. Haber 4446 ( CR!, MO!) ; Heredia: Sarapiqui, Near Puerto Viejo along road near the Río Sucio , 20 m, 27 May 1976, (Fr.), T.B. Croat 35689 ( MO!) ; Sarapiqui, Sendero entre el campamento Canta Rana y Río Peje , 400 m, 14 January 1983, (Fr.), I. Chacón 82 ( MO!) ; Heredia, Fila Carrillo , 700 m, 30 March 1984, (Fr.), L. Gómez 21131 ( CR!, MO!) ; Sarapiquí, La Virgen, Estación Biológica La Tirimbina , Sendero la Ceiba , 150 m, 6 June 2016, (Fr.), M. Cedeño et al. 899 ( USJ!) .

Figures

FIGURE 56. Monstera molinae from Sarapiquí, Costa Rica. (A) Developing inflorescence. (B) Inflorescence with open spathe, front and back views. (C) Mature infructescence, stylar plates detached. (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) Seedling. (H) Seeds. (I) Juvenile plant. (J) Adult plant flowering on free lateral shoots. M. Cedeño et al. 899 (USJ). Image from Cedeño- Fonseca et al. (2022).

FIGURE 57. Monstera molinae. Adult plant with hanging stems growing 20 m above the ground. Tilarán, Costa Rica. Photo by M. Cedeño-Fonseca. (Not collected).