MONSTERA WILSONIENSIS
PROTOLOGUE: Monstera wilsoniensis M.Cedeño & Grayum, published in Nordic Journal of Botany 38-e02970: 8 (2020).
Monstera wilsoniensis M. Cedeño & Grayum, sp. nov. Type: Costa Rica, Puntarenas: Coto Brus, San Vito, Jardín Botánico Wilson, forest preserve, 8°47′1″N, 82°58′58″W, 1350 m, 10 Oct 2018, M. Cedeño, M. Blanco, M. Mata & O. Alvarado 1484 (holotype, USJ [2 sheets]; isotypes, MO, PMA, to be distributed).
DISTRIBUTION: Costa Rica: Costa Rica.
DISTRIBUTION NOTE: Costa Rica: Puntarenas.
SPECIES DESCRIPTION:
Nomadic vine, pendent habit. Seedlings: bearing foliage leaves. Juvenile plants: root climbers; stems light green with black pustules; internodes 3–5 cm long, 4–6 mm diam.; petiole distinct, dark or light-green, smooth, 5–10 cm long, sheathed to base of the geniculum; petiole sheath deciduous; blades ovate, lanceolate, attenuate or truncate at base, acuminate at apex, subcoriaceous, 8–15 × 2–6 cm, not appressed to the phorophyte; fenestrations absent. Adult plants: root climbers; stems light-green to dark with black pustules, cylindrical; internodes 2–10 cm long, 1.0–1.5 cm diam., usually 3.0–6.6 times longer than wide; cataphylls light-green, deciduous but leaving dry fragments on the peduncle; anchor roots dark brown; feeder roots brown; petiole dark green, sometimes white-spotted, smooth, 13–20 cm long, sheathed to base of the geniculum; petiole sheath deciduous; geniculum smooth, sunken adaxially, convex abaxially, 1.0–2.5 cm long; blades lanceolate or oblique, cordate, subcordate to obtuse at base, acuminate at apex, subcoriaceous, drying greenish, yellowish or blackish, 15–25 × 13–15 cm, slightly decurrent to the medial part of the geniculum; midrib ribbed adaxially, convex abaxially, drying yellowish or blackish on both surfaces; primary lateral veins 15–25 per side, forked, slightly sunken adaxially, prominent abaxially, departing midrib at 55–65°, drying yellowish or blackish; secondary veins reticulate; collective veins visible; fenestrations absent or infrequently present; margins entire.⁴
INFLORESCENCE:
Inflorescences on ascending or pendent stems, 1–3 simultaneously at flowering time, arranged in the axils of the leaves or into cataphylls; peduncle smooth, 10–15 cm long; spathe long-acuminate or mucronate, light green during development, yellowish green externally and white internally at apex, thin, completely open, deciduous after anthesis, 13–18 × 9–13 cm, up to 4 cm longer than spadix; spadix creamy during development, yellowish-cream at anthesis, 7–13 cm long, 1.5–2.0 cm diam.; basal sterile flowers 3–5 mm long, with a transparent stigmatic secretion; fertile flowers 4–6 mm long; stamens 2–6 mm long, with laminar filaments; anthers 1–2 mm long; ovary quadrangular in longitudinal section, ribbed, 3–4 × 3–4 mm; style hexagonal, 1–2 × 3–4 mm; stigma linear, with a transparent stigmatic secretion; berries with a green stylar cap during development, mature stylar cap white-cream; pulp white; seeds black, 3–5 mm long.⁴
ECOLOGY:
Endemic to Costa Rica on the Pacific slope of the Cordillera of Talamanca, as well as the Cerros de La Carpintera, Cerros de Escazú, and Fila Costeña, from 1200 to 2100 m, in Premontane moist forest life zones. Flowering has been recorded in June and September. Fruiting in December, January and March.⁴
DISTRIBUTION MAPS:
ETYMOLOGY:
The epithet wilsoniensis refers to the Wilson Botanical Garden (part of the Reserva Biológica Las Cruces, owned by the Organization for Tropical Studies; Bates 1987), a site where this species is especially abundant.²
NOTES:
1. The species is a member sect. Monstera, and differs from the other species of its genus in Costa Rica by having petioles sheathed along their entire length, petioles sheathed deciduous, leaf blades cordate at base, scarcely fenestrate, and with numerous lateral primary veins, and inflorescences on both ascending and hanging stems. This species has been confused with the lowland morphotype on the Pacific slope of Monstera adansonii but differs from the latter by having shorter petioles 13–20 (vs. 35–55 cm) and smaller leaf blades (15–25 × 13–15 cm, vs. 25–65 × 25–45 cm) that are cordate or subcordate to obtuse (vs. cuneate or attenuate) at base. Monstera wilsoniensis grows mainly in Premontane moist forest life zones of the Las Cruces Biological Station and the Pacific slope of the Cordillera de Talamanca, at elevations of 1200–2100 m, while the Monstera adansonii morphotypes that could be confused with it grow in Tropical dry forest and Tropical moist forest at elevations of 0–900 m and have fenestrate leaf blades.⁴
2. Conservation status: Monstera wilsoniensis is protected at the Estación Biológica Las Cruces, on the Pacific versant of Parque Internacional La Amistad, and in the Zona Protectora Cerros de La Carpintera.⁵
STORY:
STORY TITLE: Described already threatened
Monstera wilsoniensis was published in 2020 from the forest preserve of the Wilson Botanical Garden at Las Cruces, where it is especially abundant, in a paper whose title names the threat to the three species it describes: the expansion of coffee plantations.² The species is protected at Las Cruces, on the Pacific side of La Amistad International Park and in the Cerros de La Carpintera and Cerros de Escazú, yet those areas are strongly impacted by agricultural expansion and the authors assessed it as Endangered.²
Before it had a name it was taken for the Pacific lowland form of Monstera adansonii. It differs in petioles of 13 to 20 cm rather than 35 to 55, in much smaller blades cordate rather than cuneate at the base, and in living at 1200 to 2100 m in premontane moist forest, where that form of Monstera adansonii does not reach.⁴ Its inflorescences are borne on both ascending and hanging stems.⁴
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Monstera wilsoniensis M.Cedeño & Grayum
2. Nordic Journal of Botany 38-e02970: 8 (2020) — protologue.
3. iNaturalist: Monstera wilsoniensis
Additional photos from iNaturalist by Jake Rehage