Monstera mittermeieri M.Cedeño, Phytotaxa

Croat, Thomas B., Cedeño-Fonseca, Marco & Ortiz, Orlando O., 2024, Revision of Monstera (Araceae: Monsteroideae) of Central America, Phytotaxa 656 (1), pp. 1-197 : 117

34. Monstera mittermeieri M.Cedeño, Phytotaxa 514(3): 217. 2021 . ( Fig. 55 )

Type: — COSTA RICA. Puntarenas. Buenos Aires. Buenos Aires. Olan, Sendero a Cerro Arbolada , 2000 m 15 January 2017, M. Cedeño, I. Chinchilla, A. Karremans & D. Bogarin 1013, (holotype USJ!, isotype MO!) .

Robust nomadic vine, with appressed-climbing habit. SEEDLINGS bearing foliage leaves. JUVENILE PLANTS: root climbers; stems light green with white dots, smooth; internodes 4–6 cm long, 3–5 mm diam.; petiole conspicuous, dark or light green, smooth, 7–12 cm long, sheathed to base of the geniculum; petiole sheath semi-persistent; blades lanceolate, attenuate or truncate at base, acuminate at apex, coriaceous, 8–13 × 2–5 cm, not appressed to the phorophyte; fenestrations 1 or 2 elongate. ADULT PLANTS: root climbers; stems light-gold, cylindrical; internodes 1–5 cm long, 1.0– 2.5 cm diam., 1–2 times longer than wide; anchor roots beige; feeder roots brown; petiole dark green, finely asperous, 40–60 cm long, sheathed to base of the geniculum; petiole sheath thin and semi-persistent; geniculum smooth, flattened adaxially, convex abaxially, 1–2 cm long; blades lanceolate or oblong, rounded, subcordate to obtuse at base, acuminate at apex, subcoriaceous, 35–55 × 14–30 cm, decurrent on geniculum (continuous with petiole sheaths), decurrent portion 2–4 mm wide; midrib grooved adaxially, convex abaxially; primary lateral veins 20–28 per side, sunken adaxially, prominent abaxially, departing midrib at 75–85°; secondary veins reticulate; collective veins visible along the margin; fenestrations present, the ones located along each side of the midrib small and roundish, the ones located farther from the midrib much larger and elongated; margins entire or pinnatilobed, due to tearing of the fenestrations that extend to the margin. INFLORESCENCES produced on ascending stems; peduncle smooth, 15–35 cm long; spathe acuminate with revolute margins, light green and pruinose externally and pale pink internally at anthesis, turning whitish after female anthesis, thick, completely open at apex, marcescent after anthesis, 15–20 × 9–12 cm, up to 5 cm longer than the spadix; spadix white during development, yellowish-cream at anthesis, 13–17 cm long, 1.5–2.5 cm diam.; basal sterile flowers green, 4–6 mm long, with a transparent stigmatic secretion; fertile flowers 5–7 mm long; stamens 2–6 mm long, with laminar filaments; anthers 2–3 mm long; ovary rectangular in longitudinal section, ribbed, 4–5 × 2–3 mm; style hexagonal, 2–3 × 3–4 mm; stigmatophore columnar, 0.5–1.0 mm long; stigma linear, with a transparent secretion; berries with a yellowish-green stylar cap during development, mature stylar cap white-cream; pulp white; seeds green, spherical, 6–8 mm long.

Distribution and ecology: — Monstera mittermeieri is endemic to Costa Rica. It is present in the Pacific watershed in the Cordillera of Talamanca, at 2000–2100 m. It lives in Premontane rain forest life zones, in the internal part of the forest, on trees with abundant bryophytes.

Phenology: —Flowering and fruiting has been recorded in January.

Discussion: —The species is a member of sect. Monstera . It differs from the other species of the genus by the rough petiole, sheathing throughout its length with the sheath persistent, the leaf blade with elongated fenestrations towards the margin, and the light green spathe, glaucous externally and pale pink internally. It could be confused with Monstera epipremnoides , but that has a mottled or whitish petiole, a deeply pinnatifid leaf blade with fenestrations on each side next to the midrib or reaching the margin, and a spathe yellowish-green externally and cream internally. In the light pink spathe coloration, it could be confused with Monstera oreophila , but M. mittermeieri differs in having the spathe thicker and persistent (vs. thin and deciduous spathe).

Additional specimens examined: — COSTA RICA. Puntarenas: Buenos Aires, Buenos Aires, Olan , Sendero a Cerro Arbolada , 2000 m, 15 Enero 2017, M. Cedeño 1012 et al. ( USJ!) ; Buenos Aires, Buenos Aires, Olan , Sendero a Cerro Arbolado , 2000 m 15 Enero 2017, M. Cedeño et al. 1011 ( USJ!) ; Puntarenas, Buenos Aires, Buenos Aires , Gira Transtalamanca , 2060 m, 24 April 2017, (Fl.), M. Cedeño et al. 1071 ( USJ!) .

Figures

FIGURE 55. Monstera mittermeieri from Puntarenas, Costa Rica. (A) Developing inflorescence. (B) Front and back views of open inflorescence. (C) Mature infructescence, stylar plates detached. (D) Fertile flower; in lateral view (left), and longitudinal section (right). (E) Stylar plate with stigma (left) and one stamen (right). (F) Sterile flower; in lateral view (left), and in longitudinal section (right). (G) Seeds. (H) Juvenile plant. (I) Adult plant. M. Cedeño et al. 1013 (USJ). Image from Cedeño-Fonseca et al. (2021a).