MONSTERA DUBIA

Species

PROTOLOGUE: Monstera dubia (Kunth) Engl. & K.Krause, published in Das Pflanzenreich IV.23B (Heft 37): 117 (1908). The protologue is reproduced below.

SYNONYMS:

HOMOTYPIC SYNONYMS: Marcgravia dubia Kunth

HETEROTYPIC SYNONYMS: Monstera acreana K.Krause; Monstera irritans Simmonds

OTHER NAMES: Chalde (Ecuador); Malanga, Mamurillo, Pantano, Oreja de Tigre (Venezuela)

DISTRIBUTION: Mexico (Veracruz, Chiapas) to S. Trop. America, Trinidad: Belize, Bolivia, Brazil North, Chiapas, Colombia, Costa Rica, Ecuador, French Guiana, Guatemala, Honduras, Mexico Gulf, Mexico Southeast, Nicaragua, Panama, Peru, Trinidad and Tobago, Venezuela, Veracruz.

DISTRIBUTION NOTE: Trinidad and Tobago: Tobago iNaturalist: Acre, Antioquia, Chiriquí, Cochabamba, Coclé, Colón-PA, Cusco, Darién, Huánuco, La Paz-BO, Loreto, Madre de Dios, Magdalena, Manabí, Meta, Napo, Orellana, Pando, Pará, Pastaza, Pichincha, Puntarenas, Putumayo, Roraima, San José, San Martín, Santa Cruz, Santander, Santo Domingo de los Tsáchilas, Sucumbíos, Tunapuna-Piarco Regional Corporation, Yaracuy.

SPECIES DESCRIPTION:

Robust nomadic vine, with appressed-climbing habit at first, then sometimes with the mature shoots free and pendent. Seedlings: filiform. Juvenile plants: root climbers; stems light brown or beige, warty, dorsoventrally compressed; internodes 3–5 cm long, 5–8 mm diam.; petiole inconspicuous, dark green, smooth, 6–10 mm long; blades obovate, cordate at base, acuminate, coriaceous, 10–18 × 6–10 cm, sometimes variegated, completely appressed to the phorophyte; fenestrations absent. Adult plants: root climbers; stems yellowish or beige, with abundant pustules that generate a warty surface, cylindrical or dorsoventrally compressed; internodes 2–6 cm long, 1.0–3.5 cm diam., 1.7–2.0 times longer than wide; cataphylls slightly deciduous; anchor roots light brown; feeder roots beige, warty; petiole light green, white-dotted, striated and pustulate at base, warty, 30–55 cm long, fully sheathed or up to 3 cm long; petiole sheath deciduous; geniculum smooth, slightly terete, 2–5 cm long; blades ovate to elliptic or oblong, widely cuneate to rounded or truncate at base, sometimes peltate, obtuse to long-acuminate at apex, subcoriaceous or chartaceous, drying greenish-gray, brownish or yellowish, 55–100 × 30–35 cm, 1.6–2.1 times longer than wide, not decurrent on the geniculum; midrib flattened adaxially, convex abaxially, drying yellowish or dark brown on both surfaces; primary lateral veins 12–25 per side, decurrent on the midrib, bifurcated in the medial part of its length, obscure adaxially, prominent abaxially, departing midrib at 65–75°, drying black or dark brown; secondary veins reticulate and prominent; collective veins not visible; fenestrations absent or present; margins entire to pinnatilobed, with 3–6 lobes per side, 1.5–2.5 cm wide where the middle lobes are narrow.⁴

INFLORESCENCE:

Inflorescences on ascending and pendent stems, 1–7 simultaneously at flowering time, subtended by cataphylls which sometimes leave dry fragments on the peduncles; peduncle smooth, light green with white dots, 5–10 cm long, 0.7–1.2 cm diam.; spathe apically short-acuminate or obtuse, light green during development, pink externally and cream internally at anthesis, coriaceous, completely open at apex, deciduous after anthesis, 8–16 × 7–13 cm, up to 1 cm longer than the spadix; spadix white during development, creamy yellow at anthesis, 7–15 cm long, 1.5–3.5 cm diam., 1.5–2.0 times longer than wide; basal sterile flowers 3–5 mm long, narrow towards base; fertile flowers 4–8 mm long; stamens 1–7 mm long, with laminar filaments; anthers 3–4 mm long; ovary flattened, rectangular in longitudinal section, ribbed, 4–5 × 2–4 mm; style 2–3 × 4–5 mm, compressed and hexagonal; stigmatophore slightly conical, 0.3–0.5 mm long; stigma circular, with a yellowish stigmatic secretion; berries with a yellowish green stylar cap during development, mature stylar cap beige-cream; pulp white; seeds dark brown with white dots, spherical or oblong, 5–7 mm long.⁴

ECOLOGY:

From Mexico to Bolivia, Venezuela, French Guiana, Brazil, Trinidad & Tobago, at elevations of 0–450 in Tropical moist forest and Tropical wet forest life zones; in primary and secondary forest, and open areas. Flowering registered in January, May, and April. Fruiting in January and April.⁴ In his report of a summer 2000 collecting trip to South America, Thomas B. Croat of the Missouri Botanical Garden listed Monstera dubia among a few aroids occurring in small islands of vegetation scattered across the savannas of southern Beni, Bolivia, along the road from Rurrenabaque toward Riberalta.⁹ The same report's summary of the Monstera found in Bolivia names Monstera adansonii, Monstera obliqua, Monstera spruceana and Monstera subpinnata, but not Monstera dubia.⁹

ETYMOLOGY:

From Latin dubius, "dubious," because the authors of the basionym Marcgravia dubia were not certain that the sterile type specimen was really a Marcgravia.⁶

NOTES:

1. The species is a member of sect. Marcgraviopsis. It differs from the other species by its smooth and mottled petiole with warts on the base, the deciduous petiolar sheath, the subterete geniculum, the entire or fenestrate leaf blade with the base cordate and sometimes peltate, the primary lateral veins bifurcated at about half their length, inflorescences subtended by deciduous cataphylls in a sympodial series between episodes of monopodial leafy growth, the externally pink spathe and slender flowers with circular stigmas. Monstera dubia is similar to Monstera punctulata, but the latter has the spathes pale green externally, the petioles verrucate and grooved throughout their length, the leaf blade usually with numerous conspicuous fenestrations between primary lateral veins and grows at elevations above 600 m, while Monstera dubia generally has a less conspicuously fenestrate leaf and grows in the lowlands of the Pacific slope. For more details about the taxonomic comments and nomenclatural notes see Cedeño-Fonseca et al. (2022).⁴

2. Conservation status: Monstera dubia is protected in the Reserva Forestal Golfo Dulce, Parque Nacional Corcovado and Parque Nacional Carara.⁵

STORY:

STORY TITLE: A name that wandered for a century

The first specimen was a juvenile shingle plant pressed flat against its tree, gathered by Humboldt and Bonpland in what is now Sucre, Venezuela, and described in 1825 as Marcgravia dubia, the epithet recording the authors' own doubt that it was a Marcgravia at all.⁶ The sterile type cannot be identified beyond the section, and the name is applied as it is because only one shingle-leaved Monstera occurs within 500 km of the type locality.⁶

Flowering material was first collected by Eggers in Ecuador in 1892 and identified as a Philodendron. Later collections were referred to various other species, and the name Monstera dubia, transferred to the genus in 1908, was applied to none of them.⁶ By 1977 the species was well collected only on Barro Colorado Island, the source of more than a quarter of its 80 specimens, because it flowers far out of reach.⁶

Growers meet it almost always as a juvenile: rounded shingling leaves set close together, somewhat thickened, with prominent white veins and little increase in size from leaf to leaf.⁷ A similar plant with thin leaves and cloudy blotches is more likely Monstera tuberculata, one whose leaves enlarge quickly and soon perforate is Monstera punctulata, and an all-green shingler that drops easily rooted side shoots is Rhaphidophora hayi.⁷

Thomas B. Croat of the Missouri Botanical Garden reported that Monstera dubia definitely changes from its shingled, mottled juvenile leaves to preadult leaves that are solid green, and never reverts to the juvenile form.¹⁰

In Costa Rica it is one of the few species of the genus that thrives in open and disturbed ground. Along the Pacific coast it colonizes African oil-palm plantations, where litter caught in the old petiole bases gives it a footing, and the inside of the spathe sometimes carries necrotic patches in which insect larvae are found.⁵

The classic account of a Monstera seedling growing toward the darkest sector of its horizon, and so toward the nearest trunk, was made on a plant published as Monstera gigantea.⁸ That name is ambiguous and probably covers Monstera tenuis or Monstera dubia.⁶

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Monstera dubia (Kunth) Engl. & K.Krause

2. Das Pflanzenreich IV.23B (Heft 37): 117 (1908) — protologue.

3. iNaturalist: Monstera dubia

4. Croat, Cedeño-Fonseca & Ortiz 2024. Revision of Monstera (Araceae: Monsteroideae) of Central America. Phytotaxa 656(1): 1–197

5. Cedeño-Fonseca, Hay & Blanco 2022. A taxonomic revision of Monstera Adans. (Araceae: Monsteroideae) in Costa Rica. Aroideana 45(1): 4–198

6. Madison 1977. A revision of Monstera (Araceae). Contributions from the Gray Herbarium of Harvard University 207: 3–100

7. Boyce 2000. Juvenile monsteroids. Aroid-L, 12 June 2000

8. Strong & Ray 1975. Host tree location behavior of a tropical vine (Monstera gigantea) by skototropism. Science 190: 804–806

9. Aroid-L mailing list, Tom Croat (forwarded by Steve Marak), November 5th, 2000

10. Aroid-L mailing list, Tom Croat, January 8th, 2007

Additional photos by Patrick Blanc