MONSTERA MEMBRANACEA
PROTOLOGUE: Monstera membranacea Madison, published in Contributions from the Gray Herbarium of Harvard University 207: 55 (1977).
DISTRIBUTION: Costa Rica to W. Panama: Costa Rica, Panama.
DISTRIBUTION NOTE: iNaturalist: Puntarenas.
SPECIES DESCRIPTION:
Nomadic vine, appressed-climbing habit. Seedlings: bearing foliage leaves. Juvenile plants: root climbers; stems dark green, smooth, cylindrical; internodes 3–8 cm long, 2–4 mm diam.; petiole distinct, light green, smooth, 3–6 cm long, sheathed up to half its length, petiole sheath persistent; blades ovate, cordate at base, acuminate at apex, membranous, 7–10 × 3–6 cm, not appressed to the phorophyte; fenestrations absent. Adult plants: root climbers; stems bright green, glossy, smooth, cylindrical; internodes 1–3 cm long, 1.0–2.5 cm diam., 1.0–1.2 times longer than wide; cataphylls with a very reduced blade, light green, deciduous; anchor roots black; feeder roots light brown; petiole light green, smooth, 25–60 cm long, sheathed up to the medial part or 5–7 cm before base of the geniculum; petiole sheath persistent; unsheathed portion terete; geniculum smooth, slightly terete, 1.0–2.5 cm long; blades ovate or elliptic, subcordate to cordate at base, obtuse at apex, membranous, drying greenish, yellowish, grayish or blackish, 18–55 × 15–30 cm, 1.1–1.8 times longer than wide, decurrent on geniculum, decurrent portion 1–2 mm wide; midrib ribbed adaxially, convex abaxially, drying reddish, blackish or yellowish on both surfaces; primary lateral veins 8–12 per side, bifurcated or trifurcated, markedly reticulated towards the margin, strongly sunken adaxially, prominent abaxially, departing midrib at 65–70°, drying yellowish, blackish; secondary veins reticulate; collective veins not visible; fenestrations absent or present, arranged in a single series near the midrib, on one or both sides; margins entire or pinnatilobed, 4–10 lobes per side.⁴
INFLORESCENCE:
Inflorescences on ascending stems, 1–5 simultaneously at flowering time, arranged in the axils of the leaves or subtended by cataphylls; peduncle smooth, 9–20 cm long, spathe long-acuminate, light green during development, yellowish-green externally and cream internally at anthesis, coriaceous, open in the medial part, closed at base and apex, deciduous as fragments post-anthesis, 10–17 × 5–9 cm, up to 5 cm longer than spadix; spadix white during development, cream at anthesis, 7–11 cm long, 1.0–3.5 cm diam., 5.4–5 times longer than wide; basal sterile flowers 4–5 mm long, with a yellowish stigmatic secretion; fertile flowers 5–7 mm long; stamens 1–2 mm long, with laminar filaments; anthers 1.5–2.0 mm long; ovary square in longitudinal section, ribbed, 2–3 × 3–4 mm; style compressed and hexagonal, 2–3 × 3.5–4.0 mm; stigmatophore slightly cupuliform, at base slightly cleft on the style; stigma circular, with a yellowish stigmatic secretion; berries with a yellowish-green stylar cap during development, mature stylar cap yellow; pulp orange; seeds globose, green with reddish dots, 4–7 mm long.⁴
ECOLOGY:
Monstera membranacea ranges from Costa Rica (Caribbean south and Central Pacific to south) to Panamá (Chirquí), at 0–800 m, in Tropical wet forest life zones. Flowering has been recorded in November, and fruiting from March to July.⁴
ETYMOLOGY:
From Latin membranaceus, "membranaceous," referring to the very thin texture of the lamina, unique in the genus.²
NOTES:
1. The species is a member of sect. Monstera. It differs from the other species of the section by its light green petiole sheathed to half of its length with persistent wings, the bright green, distinctly membranous leaf blade, the spathe yellow externally and cream internally, with its margins overlapping at the base and apex (open only in the middle), and its infructescence with the stylar layer yellow green and the fruits with orange pulp. In the pre-adult state, Monstera membranacea can be confused with Monstera filamentosa, but the latter has brown petioles, sheathed to the base of the geniculum and with the wings of the sheath deciduous.⁴
2. Conservation status: Monstera membranacea is protected in the Refugio de Vida Silvestre Mixto Gandoca-Manzanillo, Reserva Indígena de Talamanca, Reserva Forestal Golfo Dulce, Parque Nacional Carara and Parque Nacional Corcovado.⁵
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Monstera membranacea Madison
2. Contributions from the Gray Herbarium of Harvard University 207: 55 (1977) — protologue.
3. iNaturalist: Monstera membranacea
Additional photos from iNaturalist by mdoliveira, Marvin López M., Jeremy Cowan, kputirka and Oliver Ingold
Additional photo from Wikimedia Commons by Qfaceae
