Miconia vallartensis Zabalgoitia, Figueroa & Muñiz-Castro, 2020

Zabalgoitia, Alejandro, Figueroa, Dante S. & Muñiz-Castro, Miguel Á., 2020, A new species of Miconia (Melastomataceae) endemic to western Jalisco, Mexico, Phytotaxa 432 (1), pp. 1-10 : 2-7

Miconia vallartensis Zabalgoitia, Figueroa & Muñiz-Castro sp. nov. ( Figs. 1 , 2 ).

Diagnosis:— Subshrub differentiated from other species in the genus with elongate, linear-subulate and glabrous anthers by its large, flexuous glandular trichomes up to 11 mm on young branchlets and petioles, pseudolateral congested dichasial inflorescences, 5-merous flowers, and pink to dark red flowering hypanthia with reflexed calyx teeth.

Type:— MEXICO. Jalisco: Puerto Vallarta, por vereda entre las juntas del Arroyo Palo María y A. Chupalodo y la cerca del “Vacatón”, a 200 m al WNW de las juntas, ecotono de bosque mesófilo de montaña con bosque tropical subperennifolio, con presencia de Calliandra grandiflora, Zamia paucijuga, Coccocypselum sp., Pedilanthus sp., Sommera grandis , Calophyllum brasiliense, Costus pictus, Magnolia vallartensis , Podocarpus matudae , 20°31’58.30”N, 105°14’50.70”W, alt. 390 m, 4 julio 2013, Miguel Muñiz-Castro, Jesús Padilla-Lepe, Gerardo Hernández, Neil Gerlowski, Miguel Cházaro, Ricardo Díaz-Borioli 1216 (holotype IBUG!; isotypes ZEA!, MEXU!, CIIDIR!).

Perennial subshrub 0.3–1 [–1.3] m tall; young branchlets and petioles slightly pulverulent, reddish-green in color, sparingly covered with simple smooth spreading slightly flexuous trichomes 3–11 mm long with a translucent gland at the apex, white to wine red, sometimes the trichome cover denser at the nodes and forming a dense trichome ring just above the base of the petioles. Leaves opposite, isophyllous; petioles [1.9–] 5–10 [–11.1] cm long; blades [4.5–] 8–14 [–21] × [3.5–] 4.5–10 [–12] cm, widely elliptic to elliptic or ovate, with 5 nerves diverging from the same point at the base of the leaf, or if 5-plinerved then the innermost pair diverging at a maximum of 5 mm above the base of the blade, rarely with a third pair of inconspicuous veins very close to the blade margin, margins toothed, ciliolate, base rounded to slightly cordate, sometimes cuneate or oblique, apex acuminate, adaxial face lustrous, smooth, deep green when fresh, covered with spreading smooth trichomes 3–5 [–6] mm long that are adnate to the surface and broader towards the base, abaxial face papillose, sometimes foveolate, grayish-green to deep purplish-red with a metallic brightness, sparingly covered with trichomes [2–] 4–6 [–8] mm long, these denser on the veins. Inflorescence a shortly branched, congested pseudolateral dichasium 2–5 cm long with [1–] 2–15 [–20] flowers; axes of the inflorescence reddish, sparingly covered with glandular trichomes 3–8 mm long, nodes densely covered with trichomes up to 1.5 mm long; bracteoles didymous, subulate to narrowly triangular 0.5 × 1.8 mm. Flowers 5-merous, shortly pedicellate. Hypanthium [2–] 4–5 [–6] × 1.5–2.5 mm, urceolate, pink to dark red, glabrescent. Sepals 5, the inner laminar portions rounded, 0.5 × 1 mm wide, the external teeth 0.8 × 1.0 mm, triangular, reflexed, beset with an apical trichome up to 2 mm long. Petals oblanceolate to spatulate [1.1–] 1.2– 1.3 [–1.4] × 0.4–0.5 cm, the apex rounded to obtuse, pale pink to white. Stamens diplostemonous, isomorphic, slightly geniculated near the union of the filament and the anther, exerted, filaments 5–6 mm long, white to pale yellow, glabrous; anthers [3–] 4–5.5 × 0.3–0.4 mm, basifixed, oblong, attenuating towards the apex, dehiscing trough an apical pore ca. 0.14 mm diam., glabrous, white; connective as long as the thecae but 0.2–0.4 wide, ventrally sagittate, dorsally gibbous, yellow. Ovary 1.2–1.9 × 1.1–1.6 mm, half inferior, 5-locular, umbonate, smooth, glabrous; style bacilliform [9–]10–12[–13] mm long, white to pinkish; stigma inconspicuously capitated, white to pinkish. Berries 0.7–1.1 × 0.5–1.0 mm, ovoid to spherical, turning dark purple when mature. Seeds 0.4–0.5 × 0.4–0.6 mm, numerous, triangular-ovate, testa rough to slightly fluted.

Additional specimens examined (paratypes):— MEXICO. Jalisco: Cabo Corrientes, en las inmediaciones de “La Antena”, por el camino Cuapinole-Los Alacranes, al este de Las Juntas y Los Veranos, en ladera norte, 20°28’39.4’’N, 105°15’40.7’’W, alt. 600 m, 2 septiembre 2018, Zabalgoitia, Muñiz-Castro, Figueroa 540 ( IBUG!); 3.8 km al este de Las Juntas y Los Veranos, bosque tropical subcaducifolio con elementos de bosque de pino y encino, 20°28’24.7’’N, 105°15’24.2’’W, alt. 702 m, 2 septiembre 2018, Zabalgoitia, Muñiz-Castro, Figueroa 546 ( CH!, MEX!); 4 km al este de Las Juntas y Los Veranos, bosque de encino y pino, 20°28’16.5’’N, 105°15’27.7’’W, alt. 682 m, Zabalgoitia, Muñiz-Castro, Figueroa 547 ( IBUG!, CIIDIR!); en las inmediaciones de La Antena, por el camino hacia “Los Alacranes”, bosque de encino-pino con elementos tropicales, 20°28’17.0’’N, 105°15’33.5’’W, alt. 692 m, 2 septiembre de 2018, Zabalgoitia, Muñiz-Castro, Figueroa 552 ( IBUG!). Puerto Vallarta, 50 m al oeste de la unión de los arroyos Palo María y Chupalodo, bosque tropical subperennifolio con elementos de bosque mesófilo de montaña, 20°31’59.7’’N, 105°14’47.4’’W, alt. 379 m, 2 septiembre 2018, Zabalgoitia, Muñiz-Castro, Figueroa 531 ( IBUG!); ibidem, 2 septiembre 2018, Zabalgoitia, Muñiz-Castro, Figueroa 530 ( ZEA!, CIIDIR!); aproximadamente 400 m al este-sureste de la confluencia de los arroyos Palo María y Chupalodo, bosque tropical subperennifolio con elementos mesofíticos, 20°31’46.7’’N, 105°14’15.1’’W, alt. 460 m, 2 septiembre 2018, Zabalgoitia, Muñiz-Castro, Figueroa 536 ( CIIDIR!, CHAPA!); 4.7 km al sur de la desviación de los caminos de El Jorullo y Vallejo, bosque de encino-pino con elementos tropicales, 20°32’15.1’’N, 105°12’37.6’’W, alt. 505 m, 9 noviembre de 2018, Zabalgoitia, Muñiz-Castro, Figueroa 580 ( IBUG!); juntas de Arroyo Palo María y Arroyo Agua Zarca (A. Chupalodo), sub-arbusto de 1.3 m de alto, frecuente, 20°31’55.50”N, 105°14’44.80”W, alt. 340 m, 26 de junio de 2014, Muñiz-Castro, Hernández, Nuño, Vázquez 1342 ( IBUG!, ZEA!, MEXU!); cerca de las juntas de Arroyo Palo María y Arroyo Agua Zarca (A. Chupalodo), sub-arbusto de 1 m de alto, frecuente, creciendo con Conostegia xalapensis , Miconia albicans , Calophyllum brasiliense , Magnolia vallartensis , Podocarpus matudae , 20°31’55.52”N, 105°14’44.97”W, alt. 345 m, 2 septiembre de 2018 Zabalgoitia, Muñiz-Castro, Figueroa 528 ( ZEA!); ibidem, 2 septiembre de 2018, Zabalgoitia, Muñiz-Castro, Figueroa 532 ( MEXU!).

Distribution:— Miconia vallartensis is only known from a restricted area between the Horcones and Cuale rivers in the mountains south and southeast of Puerto Vallarta ( Fig. 3 ). From a biogeographical point of view, the populations of M. vallartensis known to date are located within the limits of the Sierra Madre del Sur and Pacific Lowlands provinces ( Morrone 2018). Otherwise, according to Cuanalo de la Cerda et al. (1989), these occur in the Sierra Madre del Sur terrestrial province.

Habitat and Ecology: —The species grows in areas with an interesting flora composed of tropical elements such as Cupania L. (1753: 200), Couepia Aubl. (1775: 519) and Calophyllum L. (1753: 513) mixed with elements associated with oak-pine forests of Quercus L. (1753: 994), Pinus L. (1753: 1000), Clethra L. (1753: 396) and mesophytic forest with Magnolia L. (1753: 535), Podocarpus L’Hér. ex Pers. (1807: 580) , Clusia L. (1753: 509) and Cyathea Sm. (1793: 416) .

The species can be found in semi-open and well-illuminated sites, in steep ravines or in the edge of climax forests. The predominant soils are acid Pellic Vertisols, Vitric Andosols, Chromic Luvisols, and Eutric Nitosols. The elevational range of the populations known to date is between 300 and 750 m a.s.l. with annual average temperatures of 23–24°C and precipitations of 1620–1700 mm per year ( Ruiz-Corral et al. 2018).

Phenology:— The specimens with flowers were collected between June and September, during the rainy season. Mature berries were found between July and November.

Etymology:— The epithet highlights the biodiverse territory of Puerto Vallarta, in which municipality this plant was first seen.

Ethnobotany:— Berries are consumed by the local people, who call them “pedorrilla” or “chachalaquilla”; this names are also given to the entire plant. The colorful foliage and the big flowers make this species potentially ornamental.

Conservation status:— Miconia vallartensis is only known from three localities. Because of the restricted area of its populations, coupled with the fact that it grows just a few kilometers from the rapidly growing tourist city of Puerto Vallarta, the populations are at risk. The primary risk factors are the pressures exerted on these habitats by the introduction of livestock, forest fires, global warming, suburban developments and infrastructure works. Both federal and state governments plan to start the construction of a freeway bypass around the city of Puerto Vallarta by the year 2020. This highway and its negative impacts would be located among the only three known locations of Miconia vallartensis ( BANOBRAS 2019) . Based on IUCN Red List guidelines and criteria we recommend a conservation assessment of Critically Endangered for Miconia vallartensis . It has an Extent of Occurrence (EOO) of 14.78 km 2 (<100 km 2, B1 criterion), in addition to its severely fragmented population structure [condition (a)] and an estimated continuing decline of area of occupancy [condition (b)(ii)] and quality of habitat [(b)(iii)]. The estimated Area of Occupancy (AOO) for this species was 16 km 2.

Discussion: —The genus Clidemia D. Don (1823: 284) , whose members have been recently transferred to Miconia , has traditionally comprised plants with baccate fruits, pseudolateral or pseudoterminal inflorescences and non-acute petals ( Cogniaux 1891), being all these characters present in M. vallartensis ; however, species that share this characters do not belong to a monophyletic group ( Michelangeli et al. 2004, 2008, Martin et al. 2008, Goldenberg et al. 2008), so new comprehensive works that include recently transferred species from other baccate fruits genera to Miconia are needed for the assignment of its species to infrageneric categories. On the other hand, based on Cogniaux’s (1891) sections of the genus Miconia , this new species could be placed in the Miconia section Octomeris (Naudin) Triana ex Hook.f. (1867: 764) by the elongate, linear-subulate, not glandulose anthers with one minute pore. Nevertheless, a phylogenetic analysis ( Goldenberg et al. 2008) has shown that the members traditionally assigned to this section are placed in different clades within other sections, thus, due to the convergence of some diagnostic characters, the infrageneric position of this new species is now uncertain.

Miconia vallartensis is morphologically similar to M. submontana (Rose ex Gleason) Michelang. (2019: 115) [= Clidemia submontana Rose ex Gleason (1939: 127) ], a species that has not yet been assigned to a section, and Miconia obconica Gleason & Wurdack (1968: 172) , traditionally assigned to Sect. Octomeris ( Goldenberg et al. 2013). Like M. vallartensis , both species have glabrous stamens with subulate anthers with a dorsally gibbous connective, but they differ from our species in some floral and vegetative characters, such as the shape and indumentum on the hypanthium, the size and shape of the calyx teeth, the type of inflorescence, the number of nerves in the leaves and the indumentum on branches and petioles ( Table 1).

In addition to this new species, four other species of Miconia with non-terminal inflorescences can be found in central-western Mexico: M. saxicola Brandegee (1905: 215) , M. matudae (L.O. Williams) Michelang. (2019: 104) [= C. matudae L.O. Williams (1963: 556) ], M. ruddae (Wurdack) Michelang. (2019: 112) [= C. ruddae Wurdack (1970: 388) ] and M. submontana (Rose ex Gleason) Michelang. (2019: 115) [= C. submontana Rose ex Gleason (1939: 127) ]. These species can be distinguished from M. vallartensis by the following key:

Figures

FIGURE 1. Miconia vallartensis. A. Habit. B. Flower at anthesis and detail of the inflorescence C. Flowers in bud. D. Flower dissection showing petals, hypanthium, stamens, and pistil. E. Mature fruits. F. Adaxial surface of leaf. G. Abaxial surface of leaf. Illustrations from Zabalgoitia, Muñiz-Castro, Figueroa 528, 531 and 532. Drawing by René Tapia.

FIGURE 2. Miconia vallartensis. A. Flower, frontal view. B. Flower, lateral view. C. Inflorescence with immature fruits. D. Hypanthium at anthesis. E. Branchlet with leaves and inflorescence. F. Detail of the trichomes on the stem and petioles. G. Mature fruits. H. Leaf, abaxial surface. Photos by M. Muñiz-Castro (A, B, C, D, G), D. Figueroa (F, H.) and A. Zabalgoitia (E).

FIGURE 3. Geographic distribution of Miconia vallartensis and other related species.