MONSTERA LAMERSIANA

PROTOLOGUE: Monstera lamersiana M.Cedeño & A.Hay, published in Journal of Plant Taxonomy and Geography (Webbia) 78: 111 (2023).

Monstera lamersiana M.Cedeño & A.Hay, sp. nov. Type: Costa Rica, Provincia Alajuela, Cantón San Carlos, distrito Florencia, Reserva del Hotel Talajari, 43 m, 18 Jan 2021, M. Cedeño & J. Mark Hughes 2206 (holotype USJ!; isotype MO!).

DISTRIBUTION: Costa Rica: Costa Rica.

SPECIES DESCRIPTION:

Nomadic vine, appressed-climbing. Seedlings: filiform. Juvenile plants: root climbers; stems smooth, dark green, flattened; internodes 3.5–9 cm long × 0.5–1 mm diameter; blades appressed to the phorophyte with visible petiole, dark green, smooth, 2–7 cm long, sheathed to blade base, petiole wings persistent or deciduous; blade lanceolate, cordate at the base, apex acuminate, thinly coriaceous, 7–12 × 3.5–7 cm, slightly flattened to the phorophyte, without fenestrations. Adult plants: root climbers; stem brown to light brown or beige, dorsoventrally compressed, smooth, with longitudinal striations; internodes 3–14 cm long × 1.5–2.5 mm in diameter; anchor roots; dark brown; petiole grooved at the base, adaxially flattened, dark green, 15–25 cm long, sheathed to the base of the geniculum; petiole sheath deciduous, with fibrous residues close to the apex; geniculum smooth, slightly terete, 3–4 cm long; blades oblongovate, rounded or subcordate at base, apex obtuse, thinly coriaceous, 34–38 × 28–33 cm, midrib flat on upper surface, convex below; primary lateral veins 9–11 per side, submerged on upper surface, prominent on lower surface; secondary veins pinnate and reticulate; collective vein not visible, lamina completely entire with or without fenestrations near midrib, and then perforations oval or triangular, or deeply pinnatifid, with 5–8 lobes per side, 2.5–4 cm broad, with 1–2 veins per lobe, connected by filaments.²

INFLORESCENCE:

Inflorescences: on ascending adherent stems, solitary; peduncle smooth, 4–10 cm long; spathe dark green during development, unknown in anthesis; spadix white during development, in anthesis unknown; basal sterile flowers unknown; fertile flowers unknown; anthers unknown; ovary unknown; style compressed and hexagonal, 1–2 × 3–4 mm; stigma linear; infructescence ovoid-cylindric 6.0–8.0 × 3.0–4.0 cm on a pendent peduncle; berries with a green stylar cap during development and when mature; pulp white; seeds yellowish, 4–5 mm long.²

ECOLOGY:

It is currently known only in the region of Muelle de San Carlos, at elevations of ca. 40–300 m, in the Caribbean slope. It occurs in Tropical wet forest life zones, in primary forests. Flowering time is unknown but fruiting was recorded in January.²

ETYMOLOGY:

This species is named in honour of Gijsbertus Lamers, who has generously supported exploration of both Monstera and Philodendron in Central America.²

NOTES:

1. Monstera lamersiana is similar to Monstera filamentosa, from which it differs vegetatively (in adult plants) by having a shorter petiole (15–25 cm vs. 25–55 cm in Monstera filamentosa), petiole green, (vs. cream or pink), and smaller leaf blade (34–38 cm × 28–33 cm vs. 35–105 cm × 25–40 cm), and the ripe infructescence on a hanging peduncle (vs. ripe infructescence on an erect peduncle).²

2. The species is a member of sect. Marcgraviopsis. It differs from the other species of the section by its internodes 3–14 cm long with longitudinal striations, its smooth dark green petiole striated at the base and adaxially flattened; its deciduous petiole sheath, and almost terete geniculum; the lanceolate leaf blade, rounded or subcordate at the base, with the apex obtuse; and the ripe infructescence on a hanging peduncle with the stylar layer green and the pulp white. Monstera lamersiana usually has pinnatilobate leaves, with the basal lobes connected to each other by filaments. Another characteristic of Monstera lamersina is that some individuals have the leaf blade with an entire margin and without perforations. These occur sympatrically with populations of individuals with pinnatilobed and fenestrate blades.²

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Monstera lamersiana M.Cedeño & A.Hay

2. Journal of Plant Taxonomy and Geography (Webbia) 78: 111 (2023) — protologue.

3. iNaturalist: Monstera lamersiana

Additional photo from iNaturalist by Oliver Ingold