Monstera guzmanjacobiae (Araceae), a new species from Mexico with notes on its reproductive biology Jiménez, Pedro Díaz Aguilar-Rodríguez, Pedro A. Cedeño-Fonseca, Marco Zuluaga, Alejandro Croat, Thomas B. Montano, Martin Alarcón Jiménez-Segura, Mario López-Mora, Marco Macswiney, M. Cristina Yovel, Yossi Phytotaxa 2020 2020-03-23 437 1 39 46 9V6NG Diaz Jimenez, M.Cedeno, Zuluaga & Aguilar-Rodriguez Diaz Jimenez, M. Cedeno, Zuluaga & Aguilar-Rodriguez 2020 [136,1086,244,271] Liliopsida Araceae Monstera Plantae Alismatales 2 41 Tracheophyta species guzmanjacobiae sp. nov.   Type:— MEXICO. Veracruz: Municipio Catemaco, La Palma, Selva alta perennifolia, 18º33’21’’N, 95º03’35’’W, 56 m, 31 May 2014, Pedro Díaz Jiménez & Valeria Guzmán Jacob 1305( holotype XAL!, isotypes, MEXU!, UJAT!). Hemiepiphytic herb, 1–25 mabove the ground, stems appressed-climbing and ultimately pendent. SEEDLING: terrestrial, filiform. JUVENILE PLANT: stemterete, light-green, smooth, dorsiventrally compressed, internodes 4–8 cmlong, 3–5 mmdiam. Leavescompletely adhering to surface of phorophyte; petiole not visible, 1.0– 2.5 cmlong; blade 6–9 × 5–8 cm, coriaceous, obovate, without fenestrations, occasionally with white spots abaxially, base cordate, apex short-acuminate. ADULT PLANT: anchor rootsbrown; feeder roots light beige, suberous, up to 35 cmlong; internodes 6–12 cmde long, 0.8–2.5 cmdiam., dark green, semiglossy, scaly or with a clear brown cuticle, thin, exfoliating, with few greenish pustules, rarely smooth, sulcate on one side; leaveserect or pendent; petioleopaque green, 15–25 (–30) cm long, glaucous and striated at the base, slightly white spots, smooth to geniculum, sheathed up to 1.5 cmbefore or to the base of geniculum; sheathmarcescent, remanents as fibers, apical ligule 1.5–3.0 cm de long; geniculum 0.5–3.5 cmlong, 0.4–1.0 cm diam., light green or dark, smooth or striate, terete; blade18–59 x 15–37(–40) cm, ovate to widely elliptic, chartaceous or thinly coriaceous, cordate to semi-cordate at base, acute or acuminate at apex, dark green and glossy on the upper surface, bright light green on the lower surface, drying light brown on the upper surface, matte green on the lower surface; fenestrations usually only on one side, perforations 1–4, oblong-elliptic, margins blade entire; midribsunken above, prominent below; primary lateral veins5–9 per side, raised on the lower surface, whitish; tertiary veins parallel, connected near the middle of the blade up to margin. Inflorescenceaxillary, often solitary, rarely 2 per axil, rarely erect, inclined between 40–60°, on appressed-climbing or pendent stems; peduncle 5–20 cmlong, 0.8–2.0 cm diam., green or yellowish, smooth to the apex, with greenish and white pustules at the base; spathe15–19 × 12–15 cm, green prior to anthesis, at anthesis yellowish externally and white to creamy internally, coriaceous, cucullate, obtuse or mucronate at the apex, marcescent after anthesis, up to 1 cmlonger than spadix and not enclosing it; spadix 8–16 cmlong, 2–4 cmdiam., white when immature, white-cream at anthesis; basal region of sterile flowers up to 2 cmin long, not decurrent on peduncle, tapering basally; flowers 5–7 mmlong; ovary 4–5 × 3.5–4.0 mm, square and ribbed in longitudinal-section; style 3.5–4.0 mm long, 2.5–3.5 mmwide, pyramidal and conical, stigma linear, stigmatic secretion yellowish; stamens 1–6 mmlong, filament laminar, anther 1.5–2.0 mm long; sterile flowers 4–6 mmlong, with yellowish secretion. Infructescencewith stylar cap green after anthesis, yellowish green at maturity; fruits with white pulp; seeds 6–9 × 5–7 mm, pale brown, with yellowish aril, ovate-oblong; hypocotyl thick and yellow.   Distribution, habitat and conservation status:—  Monstera guzmanjacobiaeis endemic to the Los Tuxtlas region, Mexico. It is known from the municipality of Catemaco between La Palma and the road between Tebanca and Miguel Hidalgo, at elevations from sea level to 400 m, in high evergreen rainforest, edge and the interior of the forest, as well as in live tree fences and in abandoned areas of secondary vegetation (locally known as “acahuales”). According to the IUCN Red List Categories and Criteria, the species is considered in CR and EN.  Phenology:—Flowering and fruiting was recorded in February, March, April, May, June and November.  Floral ecology and reproductive biology:—At the beginning of the flowering sequence (female phase), the spathe unfolds slightly, creating a chamber between the spathe and the spadix with a narrow opening that forms when the edge of the spathe peels away ( Fig. 4D). At the base, a second access to the flowers is created when a small hole is opened. At this time, the stigmas of the sterile flowers secrete a sticky transparent resin and emit a strong fruity odor (similar to “that of ripe melon”). The stigmas of all the flowers become receptive when they secrete a transparent to slightly yellowish fluid. In the hours or days that follow, the spathe continues inflating and gradually, expanding its opening. Before anthesis ends, the stigmas wither, the anthers emerge and the pollen is released, and then the spathe opens completely. Small insects, nitidulid beetles and drosophilid flies have been observed inside the floral chamber, and male euglossine bees (  Euglossasp.) flying and walking outside the spathe ( Fig. 4D). According to the flowering behavior of the inflorescence and to that documented in other  Monsteraspecies( Chouteau et al.2007; Prieto & Cascante-Marín 2017), it is possible that only beetles and flies are their pollinators. Once the fruits mature, a large number of ants of the genus  Acromyrmexsp.visit the infructescences, apparently to feed on the white pulp that covers the seeds ( Figs. 4B, C).   FIGURE 2.  Monstera guzmanjacobiae sp. nov. A.Young inflorescence; B.Infructescence with stylar caps mostly already detached; C.Complete flower (left) in lateral view showing an immature stamen; gynoecium in longitudinal-section (right); D.Adult plant showing pendent inflorescence and developing flagellum; E.Open inflorescence in ventral view; F.Open inflorescence in dorsal view; G.Sterile flowers, lateral view; H.Style and stigma seen from above (left); immature stamen (right); I.Seed, lateral view; J.Stolon-like seedling transforming into a juvenile shingle-leaved plant at its apex; K.Juvenile plant shingle leaved climbing plant.   FIGURE 3.  Monstera guzmanjacobiae sp. nov. A.Habit of plant ascending on a tree to over 25 m; B.Habit of plant pendent from a living fence in a pasture area; C.Scaly pendent stems ( i), petiole striate at the base ( h); D.Infructescences on ascending stems; E.Young stem showing petioles with glaucous base, marcescent petiolar sheath ( m) and apical projecting ligule 1.5 cm long ( n); F.Completely terete geniculum; G.Base of the petiole with green and white projections.  Eponymy:—The species is named in honor of Mexican biologist Valeria Guzmán Jacob from the Göttingen University, who helped to collect the typespecimen.    Additional specimens examined( paratypes):— MEXICO. Veracruz: Municipio Catemaco, La Palma, Acahual (con elementos de selva alta perennifolia), 18º33’12’’N, 95º03’41’’W,  30 m,  20 September 2018, Pedro Díaz Jiménez, P. Adrián Aguilar Rodríguez & M. Montano Alarcón1427 ( MEXU; UJAT); Municipio Catemaco, Tebanca, relicto de selva alta perennifolia, 18º22’13’’N, 95º00’56’’W,  361 m,  25 February 2019, Pedro Díaz Jiménez & M. Montano Alarcón1429 ( XAL).   FIGURE 4.  Monstera guzmanjacobiae sp. nov. A.Detachment stylar layer of a mature infructescence; Band C.Exposed seeds surrounded with white pulp, with numerous foraging ants of the genus  Acromyrmexsp.; D.Euglossine bee (  Euglossasp.), visiting the inflorescence at the beginning of the female phase of anthesis.  Notes:—In Los Tuxtlas region, although one of the most studied sites in Mexico( Guevara et al.2004),  M. guzmanjacobiaehad not been previously collected. This new species differs from others in the genus by the ligule of the petiole sheath 1.5–3 cmin length, the adult leaf blade with fenestrations (1–4 perforations) often only on one side or lacking fenestrations, the inflorescence erect or inclined, the flowers with a conical pyramidal style, the seeds with a yellowish aril and with a thick yellow hypocotyl. A unique feature in  M. guzmanjacobiaeis the yellowish coloration of the seed aril and the thick, yellow hypocotyl.   Monstera guzmanjacobiaeis the third species of  Monsterain Mexico reported to have a flowering on pendent stems and the fourth within sect.  Marcgraviopsis.Although is similar to  M. luteyniiMadison (1977: 207)and  M. maderaverdeGrayum & Karney (2012: 66), endemic species from Costa Ricaand Hondurasrespectively, both species have non-fenestrate blades (rarely in  M. maderaverde) and flowers with truncate style. In addition, this last species belongs to sect.  Tornelia. The pendent habit also occurs in the Mexican species  M. tuberculataLundell, although the latter has leaf blades two to three times smaller, rarely fenestrate, and the inflorescences are completely pendent (inclined between 40–60° and rarely erect in  M. guzmanjacobiae). Adults plants of  M. guzmanjacobiaehave leaf blades similar to those of pre-adult  M. punctulata. However, in this last species the fenestrations have varied sizes and some reach the edge of the blades. 2018-09-20 P, M, MEXU, UJAT La Palma Mexico 30 18.553333 Veracruz 21 -95.06139 4 43 2 Veracruz de Ignacio de la Llave 2019-02-25 M, XAL Mexico 361 18.370277 21 -95.01556 4 43 1