Monstera integrifolia Zuluaga & Croat, 2018

Zuluaga, Alejandro & Cameron, Kenneth M., 2018, Two new species of Monstera (Araceae: Monsteroideae) with entire leaves from Panama and Costa Rica, Phytotaxa 334 (1), pp. 1-9 : 6-9

Monstera integrifolia Zuluaga & Croat sp. nov. ( Figs. 4 , 5 )

Monstera integrifolia has small, erect, entire leaf blades (16–31cm long) lacking fenestrations at maturity. It is most similar in appearance to M. xanthospatha Madison (1977: 65–67) but differs in the minute white punctate pattern of the petiole and sheath (vs. green), shorter peduncles (9–14 vs. 13–25 cm), longer spadix (8–10 vs. 5–7 cm), and raised stylar region (vs. flat).

Type: — PANAMA. Chiriqui: Distrito Gualaca, corregimiento Hornito, Reserva Forestal Fortuna, trails near to research center Jorge L. Arauz. 1200–1500 m elevation, 82°12.8’N, 8°47’W, 31 Jan 2013, A. Zuluaga 916 (holotype: WIS!, isotypes: PMA!, MO!).

Seedling not seen. Juvenile plants with stems adpressed to the host; leaves exserted from the host at an angle less than 45 degrees, leaf blade shape the same as adult leaves but increasing gradually in size. Pre-adult and adult plants growing on vertical stems and lateral branches; stem D-shaped in cross section, flat side facing the host, 1–3 cm diameter, internodes 4–6 cm long. Leaves erect or almost erect, spreading at an angle less than 45 degrees on a vertical host, or 45–90 degrees when host is horizontal; petioles 5–10 cm long, 1–2 cm diameter, D-shaped in cross section, petiole sheathed almost its entire length, sheath marcescent, not persistent, petiole and sheath green with a minute white punctate pattern; geniculum 2–3 cm long; blades ovate to lanceolate, asymmetrical, 16–31 cm long, 7–10 cm wide, blade 1.2–1.6 times longer than petiole, coriaceous, dark green on both surfaces, paler on the lower surface, base obtuse, apex acuminate; main vein flat on the upper surface, raised on the lower surface, primary lateral veins sunken on the upper surface, raised on the lower surface, 4–8 per side, secondary lateral veins sunken on the upper surface, slightly raised on the lower surface; tertiary veins reticulate, inconspicuous. Plants flowering 3–5 m above the ground, inflorescence solitary; peduncle 9–14 cm long, 0.6–1.2 cm diameter, circular in cross section, green; spathe white at anthesis, 15–18 cm long, 8–9 cm wide, 5–8 cm longer than spadix; spadix terete, slightly narrower at apex, 8–10 cm long, 1.7–2 cm diameter, 0.6–0.9 times longer than peduncle. Flowers white, 12-14 in primary spiral, 14–17 in secondary spiral, 4–5 mm long; stamens four; filaments laminar, 3–4 mm long; anthers 2–3 mm long; ovary crosssection circular, 3–4 mm diameter; style apex narrower than ovary, conical, 1–2 mm long; stigma capitate, 1–2 mm long. Infrutescence, fruits, and seeds not seen.

Distribution and ecology:— Monstera integrifolia is only known from four collections from northern Panama and the Panama – Costa Rica border. It grows in wet and humid forests between 1000–2000 m above sea level ( Fig. 3 ).

Eponymy:— The specific epithet integrifolia refers to the entire, non-fenestrate mature leaves, a character not common in Monstera .

Notes:— Monstera integrifolia is most similar to M. xanthospatha , a species endemic to the West and Central Cordilleras of Colombia at elevations between 1500–2300 m. Both species are small plants, flowering when they are less than 10 m high on their host, and inhabiting montane cloud forests. Monstera integrifolia differs from M. xanthospatha in having shorter petioles and peduncles, a longer spadix, and flowers with raised stylar regions (vs. flat) ( Table 2.)

Additional specimens examined (paratypes):— COSTA RICA. Puntarenas: Corredores, along road between San Vito de Java and Villa Neily, 8.8 miles north of Villa Neily , 8°42’28”N, 82°56’16”W, 1010 m, 14 Jun 1987, T.B. Croat 66170 (MO) . PANAMA. Bocas del Toro: Cerro Colorado , 9.2 mi W of Chamé, along trail E of road which leads down to stream, 8°35’N, 81°50’W, 1450–1480 m, 6 Jul 1988, T.B. Croat 69067 (MO, PMA) ; Chiriquí: Along road to

Fortuna Dam site on Rio Chiriquí, N of Gualaca, 7.7 mi beyond Francisco Linare’s lane, 19.2 mi beyond bridge over Rio Esti; 9.1 mi beyond Los Planes del Hornito, 8 mi beyond jct. in road to tunnel; 1300 m, 27 Nov 1979, T.B. Croat 48742 (MO).

Figures

FIGURE 3. Distribution map of Monstera anomala (circles) and Monstera integrifolia (stars).

FIGURE 4. Comparison between Monstera integrifolia sp. nov. (A–C) and M. xanthospatha (D–G). M. integrifolia: A, adult leaf lacking fenestrations; B, detail of the petiole showing the punctuated pattern; C, young spadix showing blunt flowers. Monstera xanthospatha: D–E, Adult leaves of with and without fenestrations; F, young spadix enclosed by the spathe; G, infructescence, showing flat flowers.

FIGURE 5. Illustration of Monstera integrifolia sp. nov (Zuluaga 916). A, flower in lateral view; B, young plant; C, adult leaf; D, young inflorescence open showing spadix with blunt flowers; E, section of the stem with closed inflorescence, box showing the punctuated pattern of the petioles. Illustration by Sarah Friedrich.