Monstera gentryi Croat, M.Cedeño & O.Ortiz, 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 : 213-216

Monstera gentryi Croat, M.Cedeño & O.Ortiz , sp. nov. ( Figs. 4–5 )

Characterized by its moderately slender stem, fully sheathed with a persistent sheath, narrowly ovate inaequilateral heavily fenestrate blade, spathe to 10 cm longer than the spadix, long-acuminate, green-glaucous abaxially during development, green-glaucous or pinkish abaxially and light orange-yellow adaxially at anthesis.

Type:— PANAMA. Chiriquí: Boquete, camino hacia el Cerro Pata de Macho , aproximadamente 1.0 km desde la entrada de Tree Trek, 1748 m, 23 Sept. 2019, O. O. Ortiz, M. Cedeño, Z. Samudio & Z. Serracín 3756 (holotype PMA!, isotypes MO!, USJ!, to be distributed) .

Robust nomadic vine, with appressed-climbing habit. SEEDLINGS bearing foliose leaves. JUVENILE PLANTS root climbers; stems light or dark green, smooth; internodes 2–4 cm long, 3–7 mm diam.; petiole conspicuous, light green, smooth, 7–20 cm long, sheathed to base of the geniculum, petiole sheath persistent; blades lanceolate or ovate, subcordate to truncate at the base, acuminate at apex, 8–16 × 3.5–4.8 cm, not appressed to the phorophyte; with or without fenestrations. ADULT PLANTS root climbers; stems dark or light green, drying light brown, smooth, cylindrical; internodes 1–4 cm long, 2–4 cm diam.; anchor and feeder roots black; petiole light green or yellowish green, smooth, 34–50 cm long, sheathed to the base of the geniculum; petiole sheath persistent; geniculum smooth, sulcate adaxially, convex abaxially, 2–4 cm long; blades narrowly ovate, asymmetrically rounded at the base, sometimes obtuse in one side and rounded in the other, acuminate at apex, sub-coriaceous, drying slightly dark brown to yellowish-brown, matte above, slightly paler, yellowish-brown and faintly glossy below, 33–40 × 15.8–20.5 cm, 1.7–2.4 times longer than wide, 0.9–1.1 times longer than petiole, decurrent on geniculum, decurrent portions 0.5–1.0 mm wide; midrib ribbed adaxially, convex abaxially, drying yellow-brown; primary lateral veins 13–25 per side, departing midrib at 60–75°, strongly sunken adaxially, prominent abaxially, drying yellow-brown; tertiary veins parallel but becoming reticulated toward the margin; collective veins more or less visible; fenestrations present, usually comprising small sub-circular holes 0.6–2.5 cm long located near the midrib, these often scattered among 7–9 larger oblong elliptical perforations, each 4.0–10.5 × 1.5–3.0 cm, these often extending from near the midrib to near the outer margin, the larger perforations often tearing through to the margins; margins entire or pinnatilobed (due to tearing of the perforations that extend to the margin), 2–6 lobes per side reaching the midrib, 1–6 cm wide. INFLORESCENCES produced on ascending stems; peduncle smooth, 15–30 cm long, 5–7 mm diam.; spathe long- acuminate, green-glaucous externally during development, green-glaucous or pinkish externally and light orangeyellow internally at anthesis, 14–20 × 5–10 cm, up to 10 cm longer than the spadix; apparently persistent after anthesis; spadix white during development, creamy-white at anthesis, 9.0– 11.7 cm long, 1.3–1.8 cm diam.; sterile flowers not documented; fertile flowers 5–6 mm long; stamens with laminar filaments, 1.5–6.0 mm long; anthers 1.5–3.0 mm long; ovary rectangular and ribbed, 3–4 × 3.0– 3.5 mm; style hexagonal, 1.5–2.0 × 3.0– 3.5 mm; stigmatophore slightly columnar; stigma linear; sterile flowers 4–5 mm long; berries with creamy white stylar caps during development, mature stylar caps creamy; pulp white; seeds matte black, 4 × 5 mm.

Etymology:— The named is in honor of Alwyn Howard Gentry (1945–1993), who was an excellent professional as a botanist ( Miller et al. 1996), and who in the early 1970´s collected some of the first herbarium specimens of this species (Gentry 3080 and 7434, MO).

Distribution and ecology:— Monstera gentryi is endemic to western Panama, on both Caribbean and Pacific slopes, from eastern Chiriquí province (Cerro Pata de Macho), Comarca Ngäbe Buglé (Cerro Colorado), Bocas del Toro province (on the continental divide), Veraguas province and Coclé province, at 700–2000 m, in Lower montane rainforest and Premontane rain forest life zones.

Phenology:— Flowering has been recorded from December to April, July, September and October, and fruiting in January to May, August and September.

Discussion:— Monstera gentryi differs from the other species of the genus in Panama by its moderately slender stem, mostly short internodes, fully sheathed light brown-drying petioles with a persistent sheath, narrowly ovate, inaequilateral, heavily fenestrate blade with small, roundish perforations adjacent to the midrib and large, elongated ones extending nearly across the width of each half of the blades, as well as by the moderately long peduncle, the internally pinkish spathe, cylindroid spadix which is often creamy white at anthesis, about five times longer than wide and much shorter that the spathe.

Monstera gentryi is most easily confused with M. oreophila , but differs from the latter in being generally less robust with more slender stems, persistent petiolar sheaths, and leaf blades with less diverse perforations usually with only a few small holes and otherwise also with fewer large perforations. The upper blade surfaces of M. oreophila have the minor veins less prominent, scarcely raised with the intervening areas moderately smooth while the lower surface is evenly and prominently striate as well as densely granular. In addition, the spathe of M. oreophila is thinner and proportionately shorter in relation to the length of the spadix (the spadix of M. oreophila is 0.7 times as long as the spathe, whereas in M. gentryi the spathe is less than 0.6 times as long). While both species have short pale lineations on the upper blade surface, those of M. oreophila are less uniform and less prominent while those of M. gentryi are more both more numerous and more uniform.

Another species similar to Monstera gentryi is M. lentii , which differs by having leaf blades bearing a single row of perforations, these usually beginning very near the midrib and extending more than 2/3 of the way toward the margins, as well as by having primary lateral veins often 2–2.5 cm apart. In contrast, the leaf blades of M. gentryi have two rows of perforations usually with a series of small perforations near the midrib, and with a second larger set usually beginning very near the midrib and extending more than 2/3 of the way to the margins, and also by having the primary lateral veins much closer together, especially near the base.

Monstera gentryi is the only species in the genus that has been documented with Scarabaeidae beetles inside their spathe chamber in the female phase who managed to enter without damaging the spathe ( Fig. 5C ). Another important characteristic is the frequent presence of herbivory on its spathe and spadix ( Fig. 5D ). Grayum (1990: 663) reported finding dynastine scarab beetles in inflorescences of M. oreophila in Chiriquí, Panama, but the corresponding herbarium specimens (Grayum 6395 and 6466), originally identified as M. oreophila , are in fact specimens of M. gentryi . The label of Grayum 6395 indicates that the inflorescence produces a fruity odor during the female receptive stage of anthesis. Whether the scarab beetles act as pollinators or as the agents of the eventual damage (or both) is unknown; the legitimate pollinators of other Monstera species appear to be much smaller, nitidulid beetles and/or drosophilid flies ( Chouteau et al. 2007, 2009; Prieto & Cascante-Marín 2017).

Conservation status:— Monstera gentryi occurs in five protected areas (La Amistad International Park, Volcán Barú National Park, Fortuna Forest Reserve, Santa Fe National Park and Cerro Gaital Natural Monument). The principal threat to this species is the loss of habitat due to extensive livestock activities, which was observed mainly in those locations devoid of protection. We calculate an extent of occurrence of 11705 km 2 and an area of occupancy of 92 km 2, therefore, we suggest considering M. gentryi as a vulnerable species [VU, B1ab(i,ii,iii,iv)].

Additional specimens studied (paratypes):— PANAMA. Bocas del Toro [including some areas currently part of Comarca Ngäbe Buglé]: Ridge north of Campamiento Luchio , 2000 m, 18 March 2004, Monro & Alfaro 4476 ( BM!, INB!, PMA!) ; Cerro Colorado , 9.2 miles W of Chamé; along trail E of road which leads down to stream, 1450–1480 m, 06 July 1988, Croat 69029 ( MO!) . Chiriquí [including some areas currently part of Comarca Ngäbe Buglé]: Bocas & Chiriqui, Cerro Colorado mine area, in elfin woods on divide road, along trail into Bocas and in woods on Pacific slope, from Chami station to ca. 9 miles along road, 1100–1750 m, 27 March 1986 – 31 March 1986, Hammel & Trainer 14974 ( MO!) ; Bocas & Chiriquí Cerro Colorado mine area; in elfin woods on divide road, along trail into Bocas and in woods on Pacific slope; from Chami station to ca. 9 miles along road, 1100–1750 m, 27 March 1986 – 31 March 1986, Hammel & Trainer 14930 ( MO!) ; Road to Cerro Punta National Park from Alto Quiel and Boquete , 1850 m, 16 January 1986, McPherson 8045 ( MO!) ; Cerro Colorado; road along top, border of Chiriqui-Bocas del Toro provinces, 1500–1750 m, 13 August 1977, Folsom et al. 4725 ( MO!) ; De la estation ( Cotito ) a lo largo del camino a Los Pozos, 1200 m, [no date], Aranda & Araúz 1351 ( PMA!) ; Along Río Caldera ( Boquete region ), and on slope to the east, ca. 3.5 km NW of Bajo Mono, 1600 m, 8 February 1986, Grayum 6466 ( MO!) ; Along trail between N fork of Río Palo Alto and Cerro Pate Macho , ca. 6 km NE of Boquete, 1600–1700 m, 06 February 1986, Grayum et al. 6395 ( MO!) ; Cerro Pate de Macho , 1800 m, 6 January 1983, Schmalzel 1363 ( MO!) ; Vicinity of Cerro Colorado Copper Mine development, 28 miles above San Félix, 9–10 miles above turn off to Escopeta, 1200–1500 m, 13 March 1976, Croat 33267 ( MO!) ; Cerro Colorado, along mining road 24 mi above bridge over Río San Félix, north of village of San Félix ), 1430–1500 m, 22 November 1979, Croat 48502 ( MO!) ; 6 km past divide in road to Alto Quiel from Boquete , 1730 m, 19 February 1986, Hoover 1339 ( CM!, MO!) ; Vicinity of Cerro Colorado Copper Mine Development , 28 miles above San Felix, 9–10 miles beyond turnoff to Escopeta, 1200–1500 m, 14 March 1976, Croat 33267 ( MO!) ; Fortuna Dam area , 1070 m, 3 August 1984, D’Arcy 16015 ( MO!) ; Boquete, Corregimiento Los Naranjos, Parque Internacional La Amistad , entrando por el sitio llamado Bajo de Mono , 700–900 m, 28 January 2013, Zuluaga & Olmos 908 ( PMA!) ; Corregiemiento Los Naranjos, Parque Internacional La Amistad, entrando por el sitio llamado Bajo de Mono , 700–900 m, 28 January 2013, Zuluaga et al. 907 ( PMA!) ; Bajo Mojo Chorro trails out of Boquete , 01 June 1972, Luteyn 3066 ( DUKE!) ; Vicinity of Boquete, SW slope of Cerro Pate de Macho , 1630–1780 m, 18 June 1987, Croat 66379 ( MO!) ; San Felix, Above San Felix along mining road 18 –27 milers off of Pan-Am Highway (above Chame or turnoff to Escopeta), 1200–1500 m, 12 March 1976, Croat 33154 ( F!) . Coclé: El Valle, vicinity of La Mesa near Mr. Furlong’s finca, 900 m, 12 May 1973, Gentry 7434 ( MO!) ; Plants purchased in El Valle market, plants from Mesa, 17 April 1977, Folsom 2660 A ( MO!) ; Cerro Tigrero , 1000–1350 m, 26-28 September 2001, Mendieta 17–421 ( PMA!) ; Cerro Pilón (above El Valle de Antón ), 13 April 1971, Croat 14337 ( MO!) . Veraguas: Santa Fe , Corregimiento El Pantano, Parque Nacional Santa Fe, Alto Los Gonzales o Alto El Viro, 800–1000 m, 16 January 2013, Zuluaga et al. 890 ( PMA!) ; Corregimiento Santa Fe, Parque Nacional Santa Fe , sendero tercer Brazo , cerca de la cabaña del Parque, 17 January 2013, Zuluaga et al. 889 ( PMA!) ; Cerca de El Cinco , 1000 m, 20 February 2010, Ibáñez et al. 6186 ( PMA!) ; Mountains , 3.5–4.5 mi above Santa Fé, 700–800 m, 13 December 1971, Gentry 3080 ( MO!) ; Slopes of Cerro Tute, near Escuela Agricola Alto Piedra , NW of Santa Fé; 1000–1050 m, 30 November 1979, Croat 48923 ( MO!) .

Figures

FIGURE 4. Monstera gentryi from Panama. A. Mature infructescence, stylar plates detached in the middle part. B. A longitudinal cut of the inflorescence in female anthesis, showing adaxial (internal) surface of spathe. C. Developing inflorescence.D. Fertile flower, in lateral view (left), and longitudinal section (right). E. Seeds. F. Portion of juvenile shoot. G. Sterile flower in lateral view (left) and in longitudinal section (right). H. Portion of adult shoot. I. Stylar plate, top view (left), and individual stamen (right). (Based on Ortiz et al. 3756).

FIGURE 5. Monstera gentryi from Panama. A. Adult plant. B. Mature infructescence, most stylar plates detached. C. Longitudinal cut of the inflorescence in female anthesis with Scarabaeidae beetles inside. D. Inflorescence with herbivory.