MONSTERA COLOSSICA
PROTOLOGUE: Monstera colossica M.Cedeño & O.Ortiz, published in PhytoKeys 267: 116 (2025).
Monstera colossica M.Cedeño & O.Ortiz, sp. nov. Type: Panama • Provincia Chiriquí: distrito Gualaca, camino a Bosque Protector de Palo Seco, 1 September 2018, 1100 m elev., O. Ortiz, H. Hentrich, M. Cedeño, P. Diaz-Jiménez, and R.M. Baldini 2730 (holotype PMA!).
DISTRIBUTION: Panama.
DISTRIBUTION NOTE: Panama: Bocas del Toro, Chiriquí.
SPECIES DESCRIPTION:
Robust appressed-climbing nomadic vine. Seedlings: unknown. Juvenile plants: root climbers; internodes 2.0–4.0 cm long, 5.0–7.0 mm diam.; petioles 22–30 cm long; sheathed up to ca. 5 cm before geniculum; leaves appressed to the phorophyte with visible petiole, blades 18– 28 cm long, 12–18 cm wide, 1.3–1.5 times longer than broad, abruptly acumi nate at apex; collective veins 3.0–5.0 mm from margin; margin entire or rarely pinnatilobed. Adult plants: root climbers; stems light or dark green, white punctulate, smooth, cylindrical; internodes 1.5–4.0 cm long, 4.0–7.0 cm diam., medium green, semi-glossy; petioles 50–65 cm long, densely and conspicu ously white punctulate, especially towards base, equally as long as or 1.1 times longer than blades, sheathing to the base of the geniculum to ca. 10 cm below it, free portion sulcate; petiole sheath deciduous; geniculum sulcate adaxially and convex abaxially, 4.0–7.0 cm long; blades 47–70 × 28–40 cm, narrowly ovate-elliptic, mostly entire, more or less equilateral, subcoriaceous and slight ly bicolorous, dark green and semi-glossy above, moderately paler and matte below, drying dark brown and weakly glossy above, greenish-yellow-brown and semi-glossy below, short-acuminate at apex, subcordate at base; mid-rib broad ly sunken and concolorous above, narrowly rounded and paler below; primary lateral veins 20–25 per side, narrowly sunken above, convex and slightly pal er green below, diverging at 50–70°, sometimes branching with two to three branches within 1.0–3.0 cm from the mid-rib; secondary veins parallel and reticulate towards the margin; collective vein visible; fenestrations absent or present; when present, in two or three rows along the mid-rib, usually compris ing small sub-circular holes 1.0–5.0 cm diameter, near the mid-rib; margins entire, but sometimes the larger perforations tearing through to the margins.²
INFLORESCENCE:
Inflorescence solitary; peduncle 20–22 cm long; spathe 15–32 cm long, 25 cm wide when flattened, coriaceous, whitish; spadix 18–22 cm long, 3–4 cm diam., greenish; basal sterile flowers 4.0–5.0 mm long; fertile flowers 7.0–9.0 mm long; stamens 3–8 mm long, with laminar filaments; ovary rectan gular in longitudinal section, 4.0–6.0 × 2.0–3.0 mm; style hexagonal and with stigmatophore slightly conical; stigma linear; berries with a creamy stylar cap during development, ripe berry colour unknown; seeds unknown.²
ECOLOGY:
Monstera colossica is endemic to Panama, known only from the type locality on the border of Chiriquí and Bocas del Toro Provinces and in Cerro Colorado at 1450–1480 m elevation in a Premontane rainforest life zone. Flowering time in November; mature fruits in June.²
ETYMOLOGY:
The specific epithet “colossica” is derived from the Latin colossus, itself from the Greek kolossos (κολοσσός), meaning “giant statue” or “colossus”, highlighting the plant’s overall massive and striking appearance.²
NOTES:
1. Monstera colossica differs from Monstera titanum in having primary lateral veins pale green abaxially and with 2–3 branches close to the mid vein (vs. primary lateral veins never branched and white), short peduncle 22 cm long (vs. 25–48 cm long), short spathe up to 32 cm long (vs. spathe up to 47 cm long), style hexagonal with stigmatophore slightly conical (vs. style pyramidal and distally cylindrical) and always appressed-climbing (vs. appressed terrestrial on rocks or appressed-climbing).²
STORY:
STORY TITLE: Land of giants
Monstera colossica was described in 2025 from the border of Chiriquí and Bocas del Toro provinces, one of two pachycaul giants published together from Panama, the other being Monstera corana.² The epithet comes from the Latin colossus and the Greek kolossos, a giant statue, for the plant's massive and striking build.² Its spathe reaches 32 cm and its spadix 22 cm; ripe fruit and seeds are unknown.²
Its nearest relative is Monstera titanum of the same region, the species with the largest inflorescence in the genus. Monstera colossica has primary veins pale green beneath and branched near the midrib, a shorter peduncle and spathe, a hexagonal style, and it always climbs appressed to its host, whereas Monstera titanum will also sit on bare rock.² With Monstera gigas, whose leaves exceed 3 m, the mountains of western Panama now hold three of the largest monsteras known.³
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Monstera colossica M.Cedeño & O.Ortiz
2. PhytoKeys 267: 116 (2025) — protologue.
Additional photos by Sam Smith