Monstera mittermeieri M.Cedeño, 2021

Cedeño-Fonseca, Marco, Ortiz, Orlando O., Zuluaga, Alejandro, Croat, Thomas B. & Blanco, Mario A., 2021, A reexamination of Monstera oreophila (Araceae: Monsteroideae) and description of two new pinkish-spathed species of Monstera from Costa Rica and Panama, Phytotaxa 514 (3), pp. 205-220 : 217-219

Monstera mittermeieri M.Cedeño , sp. nov. ( Fig. 6 )

Characterized by the rough petiole, sheathed throughout its length with the sheath persistent, the leaf blade with elongated fenestrations towards the margin, the spathe light green during development, light green and pruinose abaxially and pale pink adaxially at anthesis.

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

Robust nomadic vine, with appressed-climbing habit. SEEDLINGS bearing foliose 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 the base of the geniculum; petiole sheath semi-persistent; blades lanceolate, attenuate or truncate at the base, acuminate at apex, coriaceous, 8–13 × 2–5 cm, not appressed to the phorophyte; with 1 or 2 elongate fenestrations. ADULT PLANTS root climbers; stems light-gold, cylindrical; internodes 1–5 cm long, 1.0– 2.5 cm diam.; anchor roots beige; feeder roots brown; petiole dark green, finely asperous, 40–60 cm long, sheathed to the 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 the base, acuminate at apex, sub-coriaceous, 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°; tertiary 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 perforations 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, persistent 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.; sterile flowers green, 4–6 mm long, with a transparent stigmatic secretion; fertile flowers 5–7 mm long; stamens with laminar filaments, 2–6 mm long; anthers 2–3 mm long; ovary rectangular and 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.

Etymology:— This species is named in honor of Michael Mittermeier, former aroid curator at Fairchild Tropical Botanic Garden, whose passionate interest in Monstera and other Araceae has led to helpful support for our project in Central America.

Distribution and ecology:— Monstera mittermeieri is endemic to Costa Rica. It is presently known only from the Pacific slope in the Cordillera of Talamanca in the Buenos Aires county of Puntarenas province, at 2000–2100 m, in Premontane rain forest life zone in the forest understory on trees with abundant moss.

Phenology:— The flowering has been recorded in January and April, and fruiting has been recorded in January.

Discussion:— Monstera mittermeieri differs from the other species of the genus in Costa Rica by the finely asperous petiole which is sheathed throughout its length, semi-persistent sheath, and the leaf blade with elongated fenestrations towards the margin. It differs also in the light green spathe with glaucous external surface and pale pink internal surface, that turns whitish after anthesis. It could be confused with M. epipremnoides , but the latter has a mottled or white petiole, a deeply pinnatifid leaf blade with fenestrations on each side next to the central nerve or reaching the margin, and a spathe yellowish-green externally and cream internally. This species could also be confused with M. oreophila , but it differs in having a thicker spathe that remains erect and persists after anthesis (vs. a thinner spathe that becomes torn basally and reflexed-pendulous during the female stage of anthesis and drops soon after).

Monstera mittermeieri was treated as ‟ Monstera sp. A ” in Cedeño-Fonseca (2019).

Conservation status:— Currently, there is insufficient information to produce a conservation assessment based on distribution or population status for this species; we therefore propose Monstera mittermeieri to be listed as Data Deficient (DD).

Additional specimens studied (paratypes):— COSTA RICA. Buenos Aires, Buenos Aires, Olan , sendero a Cerro Arbolado , 2000 m, 15 January 2017, Cedeño 1012 et al. ( USJ!) ; Buenos Aires, Buenos Aires, Olan , Sendero a Cerro Arbolado , 2000 m, 15 January 2017, Cedeño et al. 1011 ( USJ!) ; Puntarenas. Buenos Aires, Buenos Aires , 2060 m, 24 April 2017, Cedeño et al. 1071 ( USJ!) .

The Monstera oreophila species complex:— The three species treated here comprise a well-defined species complex of southern Central America, characterized by the following traits: 1) seedlings with foliose leaves (see Introduction); 2) juveniles with non-shingling leaves; 3) leaf blades with margins decurrent on the geniculum; 4) blade fenestrations forming two series, the first comprised by small, roundish perforations adjacent to the midrib, and the second comprised by larger, elongate perforations that extend almost to the leaf margin (occasionally breaking it); 5) inflorescences produced only on ascending shoots appressed to the bark of the phorophyte; 6) spathes peach or salmon pink colored, at least on the internal surface; 7) inflorescences with a fruity scent during the female receptive stage of anthesis (but the scent not yet recorded for M. mittermeieri ); and 8) preference for cloud forest habitats at 1000–2400 m (rarely under 900 m elevation).

Monstera epipremnoides appears to be a close relative; however, we do not include it as a member of this complex because the second series of leaf perforations usually break through the margin, making the blades appear deeply pinnatifid, its open spathes are cream-colored internally instead of pink, and (as far as we have been able to ascertain) the inflorescence does not have a fruity scent during the female stage of anthesis.

Figures

FIGURE 6. Monstera mittermeieri from Costa Rica. A. Developing inflorescence. B. Front and back views of open inflorescence. C. Mature infructescence, stylar plates detached from the middle portion. D. Fertile flower, in lateral view (left), and longitudinal section (right). E. Stylar plate, top view (left), and individual stamen (right). F. Sterile flower in lateral view (left) and in longitudinal section (right). G. Seeds. H. Portion of juvenile shoot. I. Portion of adult shoot with spathe turning whitish after anthesis. (Based on M. Cedeño et al. 1013).