MONSTERA DONOSOENSIS
PROTOLOGUE: Monstera donosoensis Croat, M.Cedeño & O.Ortiz, published in Webbia 76: 269 (2021).
Monstera donosoensis Croat, M.Cedeño & O.Ortíz, sp. nov. Type: Panama. Colón: Donoso District. Minera Panamá copper-mining concession, slopes and ridges in drainage of Quebrada Brazo, 243 m, 30 Aug 2014, M.Grayum, G.McPherson, C.Ramos, I.Vergara-Pérez & L.Rojas 13242 (holotype, PMA!; isotype, MO-6636330!).
DISTRIBUTION: Panama: Panama.
DISTRIBUTION NOTE: Panama: Coclé, Colón, Darién, Guna Yala, Veraguas.
SPECIES DESCRIPTION:
Robust nomadic vine, appressed-climbing habit. Seedlings: bearing foliose leaves. Juvenile plants: root climbers; stems light green or beige, sometimes white-dotted, smooth, cylindrical; internodes 2–5 cm long, 0.5–1.0 cm diam.; petiole distinct, light green, smooth, 8–15 cm long, sheathed to base of the geniculum; petiole sheath deciduous or slightly persistent; leaf-blades ovate to lanceolate, attenuate or cuneate at base, acuminate, subcoriaceous to coriaceous, 10–25 × 9–15 cm, not appressed to the phorophyte; fenestrations absent or present, only on one side of the lamina. Adult plants: root climbers; stems beige to light brown, smooth, cylindrical; internodes 1–4 cm long, 1–5 cm diam., 0.8–1.0 as long as wide; anchor roots light brown or beige; feeder roots corky, dark brown; petiole dark green, scarcely white-dotted, smooth, 22.0–41.5 cm long, fully sheathed, or for up to 15 cm; petiole sheath deciduous or slightly persistent, horizontally open; geniculum smooth, sunken adaxially, convex abaxially, 0.5–3.0 cm long; blades ovate to elliptic, rounded or truncate at base, subcoriaceous to coriaceous, obtuse to short-acuminate at apex, drying glossy, beige or brownish, 26.5–47.0 × 16.3–25.0 cm, 1.62–1.88 times longer than wide, decurrent on the geniculum, decurrent portion 1–2 mm wide; midrib ribbed adaxially, convex abaxially, drying light or reddish brown on both surfaces, primary lateral veins 6–20 per side, strongly sunken adaxially, prominent abaxially, departing the midrib at 50–60°, drying brownish or reddish, secondary veins prominent and parallel, reticulate toward the margin; collective veins slightly visible toward lobes; fenestrations absent or present; margins entire, pinnatilobed or scarcely pinnatifid, with 2–8 lobes per side.⁴
INFLORESCENCE:
Inflorescences on ascending stems; peduncle smooth, 11.5–19.0 cm long; spathe obtuse to short-acuminate, light green during development, yellowish or cream externally and white or creamy internally at anthesis, completely open, marcescent after anthesis, 10–20 × 6–10 cm, up to 2 cm longer than the spadix; spadix white or cream (both during development and at anthesis), 9.0–10.5 cm long, 1.8–2.5 cm diam., 4.1–4.2× longer than wide; basal sterile flowers 4–6 mm long, with an orange stigmatic secretion; fertile flowers 5–9 mm long; stamens 2.0–6.5 mm long, with laminar filaments; anthers 1.3–2.0 mm long; ovary rectangular in longitudinal section, ribbed, 3–4 × 1.5–2.5 mm; style hexagonal and strongly conical, distally cylindrical, 2–5 × 2–3 mm; stigma circular, with an orange stigmatic secretion; berries with a light or dark green stylar cap during development, mature stylar cap cream-yellowish; pulp unknown; seeds unknown.⁴
ECOLOGY:
Monstera donosoensis is endemic to Panama, knowm from Coclé, Colón, Veraguas, Guna Yale, Panamá Oeste and Panamá, at elevations of 100–1600 m, in Premontane rainforest life zones. Flowering in September to November. Fruiting occurs mostly February, September to November.⁴
ETYMOLOGY:
The species is named after Donoso District, Colón Province, Panama, in which the type was collected.²
NOTES:
1. Monstera donosoensis is characterized by its dark green petioles with a deciduous or slightly persistent sheath, entire, pinnatilobed, or scarcely pinnatifid leaf blades, with or without fenestrations, spathe yellowish or cream externally and white or creamy internally, and flowers with the style hexagonal, strongly conical, and distally cylindrical.²
2. The species is a member of sect. Monstera and is characterized by its thick stems with moderately short internodes, long, nearly fully sheathed petioles, with the sheath deciduous or slightly persistent, and moderately coriaceous, dark brown-drying, usually sparsely perforate, ovate-elliptic, and weakly acuminate leaf blades, inequilaterally subrounded to acute at base, with the primary lateral veins heavily aggregated near base and the perforations (when present) large and few, mostly beginning near the midrib, as well as by its long-pedunculate inflorescences with the spathe greenish, cream-colored within, and the spadix about 2/3 as long as the spathe, and especially by its flowers with a protruding, hexagonal, strongly conical and distally cylindrical style. Monstera donosoensis is similar to Monstera dissecta (Schott) Croat & Grayum (1987), but differs in having petioles speckled with white dots, with the sheath deciduous or slightly persistent, coriaceous leaf blades, and flowers with a hexagonal, strongly conical, and distally cylindrical style. Monstera donosoensis has similar characteristics to the South American Monstera adansonii Schott subsp. klotzschiana (Schott) Mayo & Andrade (2013), but the latter differs in having dark green, less frequently mottled petioles with the sheath persistent and slightly coriaceous leaf-blades.⁴
3. Conservation status: The distribution of this species includes at least 10 locations of which seven are in protected areas. It has an EOO of 29, 214.84 km2 and an AOO of 104 km2, therefore, Monstera donosoensis could be assessed as Least Concern [LC].²
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Monstera donosoensis Croat, M.Cedeño & O.Ortiz
2. Webbia 76: 269 (2021) — protologue.
3. iNaturalist: Monstera donosoensis
Additional photos from iNaturalist by Oliver Ingold and ramon_d