Monstera filamentosa Croat & Grayum, Phytologia

Croat, Thomas B., Cedeño-Fonseca, Marco & Ortiz, Orlando O., 2024, Revision of Monstera (Araceae: Monsteroideae) of Central America, Phytotaxa 656 (1), pp. 1-197 : 80-83

18. Monstera filamentosa Croat & Grayum, Phytologia 82: 43. 1997. ( Figs. 34 , 35 )

Type: — COSTA RICA. Heredia: S base of Cerros Sardinal, Chilamate de Sarapiquí (N side of Río Sarapiquí), 4 Jul 1985, M. Grayum & B. Hammel 5539 (holotype MO!, isotype CR!) .

Nomadic vine, appressed-climbing and pendent. SEEDLINGS: filiform. JUVENILE PLANTS: root climbers; stems dark green, dorsoventrally compressed; internodes 3–5 cm long, 2–4 mm diam.; blades appressed to the phorophyte. ADULT PLANTS: root climbers; stems brown to light brown, dorsoventrally compressed and markedly sulcate on one side; internodes 3–4(10) cm long, (0.6) 1–2 cm diam., 2–3 times longer than wide; cataphylls pink, marcescent and fibrous; anchor roots black; feeder roots dark brown; petiole brown, grooved at base and smooth towards the geniculum, slightly terete at apex, 25–55 cm long, sheathed to base of the geniculum or 2 cm below it; petiole sheath deciduous with fibrous residues; geniculum smooth or striated, grooved adaxially, convex abaxially, 3–5 cm long; blades narrowly elliptic to lanceolate-oblong, broadly cuneate to rounded or cordate to subcordate at base, acuminate at apex, membranous, drying light green, yellowish or dull beige, 35–105 × 25–40 cm, not decurrent on geniculum; midrib flattened adaxially, convex abaxially, drying light or yellowish brown on both surfaces; primary lateral veins 12–30 per side, departing midrib at 80–90°, sunken adaxially, prominent abaxially, drying yellowish or light brown; secondary veins prominent and reticulated; collective veins present along the margins of the lobes; fenestrations present, arranged along midrib with filamentous strands connecting between the lobes; margins deeply pinnatifid, 6–15 lobes per side, each 2–3 cm wide, each lobe with 1 or 2 veins and a collective vein along the margin. INFLORESCENCES on ascending stems, 1 or 2 simultaneously at flowering time, arranged into cataphylls; peduncle smooth, 4–10 cm long; spathe dark green during development, pink externally and pale pink internally at anthesis, deciduous at the end of anthesis; spadix white during development, cream at anthesis, 6–11 cm long, 1.5–2.5 cm diam., 4.1–4.5 times longer than wide; basal sterile flowers 4–5 mm, with a transparent stigmatic secretion; fertile flowers 5–8 mm long; stamens 2–6 mm long, with laminar filaments; anthers 2–3 mm long; ovary quadrangular in longitudinal section, ribbed, 3–4 × 2–3 mm; style compressed and hexagonal, 1–2 × 3–4 mm; stigma linear, sunken over style; berries with a green stylar cap during development, mature stylar cap dark green; pulp white; seeds yellowish and light brown with white dots, 4–6 mm long.

Distribution and ecology: — Monstera filamentosa ranges from Costa Rica to extreme NW Colombia at 0–700 m, in Tropical wet forest and Premontane rain forest life zones.

Phenology: —Flowering in January, April, July-September. Fruits in August-September, and January.

Discussion: —The species is a member of sect. Marcgraviopsis . It differs from the other species of the genus in Costa Rica by its brown petiole, grooved at base and smooth toward the geniculum, adaxially flat and abaxially convex, the petiolar sheath deciduous with fibrous residues, the leaf blade pinnatifid (with the lobes themselves weakly pinnately lobed) and fenestrate on each side next to the midrib with very slender filaments connecting the lobes, each lobe with a distinct submarginal collective vein and the spathe dark green during development, pink externally and pale pink internally at anthesis ( Cedeño-Fonseca et al. 2022).

Monstera filamentosa is a seldom-collected species in Costa Rica; the majority of the collections are sterile or include only the spadix. The spathe color notes derive from the first and second author’s field observations. Madison (1977) treated material of this species as Monstera punctulata , from which it is amply distinct ( Cedeño-Fonseca et al. 2022).

Additional specimens examined: — COLOMBIA. Chocó: East side, Serrania del Darien, approached fromAcandi. Slightly disturbed forest, near (small) Finca Las Cascadas, 08°30’N 077°20’W, 80–100 m, 9 Jan. 1983, A. Juncosa 590 ( MO!, US!) . COSTA RICA. Heredia: Sarapiquí, La Virgen, Area between Río Peje and Río Sardinalito, Atlantic slope of Volcán Barva , 495 m, 8 April 1986, (Infer.), M.H. Grayum 6890 ( CR!, MO!) ; Sarapiqui, Zona Protectora, N slopes of Volcán Barba 300–400 m, 18 January 1983, (Fr.), M.H. Grayum 3172 ( MO!) ; Limón: Pococí, Colorado, Cerro Coronel , E of Laguna Danto , Tall evergreen forest on gentle to moderately steep slopes, 75 m, 15 September 1986, (Infer.), W. Stevens & O. Montiel 24366 ( CR!, MO!) ; Siquirres, Pacuarito, Forested ridges and slopes between Río Pacuare and Quebrada Diablo, ca. 2.5 km E of Siquirres, 150 m, 5 October 1986, (Infer.), M.H. Grayum et al. 7701 ( CR!) ; Matina, Batán, Cordillera de Talamanca , Ridge between separating Quebrada Cañabral from Río Barbilla, and slopes leading down to the latter, 300 m, 4 September 1988, (Fr.), M.H. Grayum 8762 ( CR!, MO!) ; Pococí, Colorado, Cerro Coronel , E of Laguna Danto, Tall evergreen forest on gentle to moderately steep slopes, 75 m, 16 January 1986, (Infer.), W. Stevens 23789 ( CR!, MO!) ; Pococí, Colorado , R.N. V.S. Barra del Colorado, Forests and pastures between Río Chirripocito and pastures between Río Chirripocito and Río Sardina (”Sardinal” on Chirripó Atlántico quadrangle), m, 21 April 1990, (Infer.), M.H. Grayum 9808 ( CR!, MO!) ; Pococí , Colorado , P.N. Tortuguero, Lomas de Sierpe, 1 km al O del puesto del P.N. en el Río Sierpe, Topografía Quebrada con pendientes medianamente pronunciadas, Suelo bien drenado, 100 m, 11 August 1998, (Fr.), R. Robles et al. 2001 ( CR!, MO!) ; North end of Tortuguero National Park and near the Bocas de las Lagunas de Tortuguero , Swamp forest, 0–30 m, 23 September 1978, (Infer.), W. Burger 11279 ( MO!) ; Hamburg Finca , 55 m, 19 February 1926, (Infer.), P. Standley 48874 ( MO!) ; Puntarenas: Osa , Sierpe, R.F. Golfo Dulce, Península de Osa, Along road between Rincón de Osa and Rancho Quemado, ca. 10 km W of main Rincón-Pto. Jiménez, 100 m, 4 March 1985, (Infer.), T.B. Croat & M.H. Grayum 59751 ( CR!, MO!) ; Golfito, Golfito , Sobre Fila Golfito , 400 m, 9 June 2000, (Fl.), L. Acosta 1676 ( CR!) ; Osa, Sierpe, Aguabuena , margen izquierda de Quebrada El Campo, 200 m, 22 September 1990, (Infer.), G. Herrera 4352 ( CR!, MO!) ; Parque Nacional , Sector Esquinas , 200–300 m, 12 September 1996, (Infer.), T.B. Croat 79293 ( INB, MO) ; Puntarenas, Golfito, Puerto Jiménez , Los Mogos , 40 m, 24 March 2018, (Fl.), M. Cedeño et al.1352 ( USJ!) ; Puntarenas, Golfito, Golfito , Camino hacia las Antenas , 389 m, 4 February 2019, (Infer.), M. Cedeño & A. Hay 1627 ( USJ!) . PANAMA. Bocas del Toro: Along road between Fortuna Dam and Chiriquí Grande, 7.3 mi N of bridge over Fortuna Dam, 3.2 mi N of Continental Divide. [Coordinates on orginal label: 08º45’N 82º15’W], 08°49’00”N 082°12’36”W, 700 m, 10 March 1985, T.B. Croat & M.H. Grayum 60233 ( MO!) ; Colón: Santa Rita ridge road; ca. 22 km from transisthmian highway. In forest on ridges, slopes and draws near end of road, 09°25’N 079°40’W, 500 m, 17 February 1986 – 18 February 1986, B.E. Hammel et al. 14499 ( MO!) ; Teck Cominco Petaquilla mining concession. Collected with M. Merello , 08°49’39”N 080°40’28”W, 200 m, 21 February 2008, G. McPherson 20123 ( MO!) ; Teck Cominco Petaquilla mining concession , 08°49’28”N 080°39’29”W, 180 m, 21 September 2007, G. McPherson 19759 ( MO!) ; Santa Rita Ridge Road , along trail at end of road which goes to Río Indio, beginning 10.6 km from Iransisthmiam Hwy, 3 km beyond hydrographic station, 09°22’30”N 079°41’30”W, 380 m, 13 Apr. 1976, T.B. Croat 34337 ( MO!) ; Darién: Pinogana. Along headwaters of Río Tuquesa, ca. 2 km air distance from the Continental Divide, in vicinity of upper gold mining camp of Tyler Kittredge, 08°33’30”N 077°29’00”W, 600 m, 25 August 1974, T.B. Croat 27179 ( MO!) ; San Blas: El Elano-Cartí Road , 14 mi N of Panamerican Highway, 09°21’N 078°57’W, 300 m, 12 July 1988, T.B. Croat 69243 ( MEXU, MO, NY, PMA, TEX) ; Along El Llano-Cartí road, 10.5 miles from Interamerican Highway, 09°21’30”N 078°58’00”W, 550 m, 14 March 1985, T.B. Croat 60488 ( MO!) .

Figures

FIGURE 34. Monstera filamentosa from Golfito, Costa Rica. (A) Developing inflorescence. (B) Inflorescence in female anthesis with pink spathe. (C) Mature infructescence, stylar plates detached. (D) Sterile flower; lateral view (left) and longitudinal section (right). (E) Fertile flower; in lateral view (left) and in longitudinal section (right). (F) Seeds. (G) Stylar plate with stigma (left) and one stamen (right). (H) Juvenile plant. (I) Adult plant. (J) Pre-adult plant. M. Cedeño et al. 1352, 1627 & 1704 (USJ). Image from Cedeño-Fonseca et al. (2022).

FIGURE 35. Monstera filamentosa from Golfito, Costa Rica. (A) Stem with fibrous remains of cataphylls (black arrow). (B) Petiolar sheath with fibrous residues (white arrow). (C) Part of the leaf blade shows filaments connecting the lobes (arrow ii) and marginal collecting veins in each lobe (arrow i). (D) Pale pinkish young cataphylls (white arrow). M. Cedeño et al. 1704 (USJ). Image from Cedeño- Fonseca et al. (2022).