Miconia portogallensis de Santiago & Michelang., 2016

Gómez, Jesús Ricardo De Santiago & Michelangeli, Fabián A., 2016, Miconia portogallensis (Melastomataceae) a new species from the Sierra Madre del Sur, Guerrero, Mexico, Phytotaxa 278 (2), pp. 132-140 : 133-137

Miconia portogallensis de Santiago & Michelang. sp. nov.

A dioecious species of Miconia section Cremanium that can be distinguished by the presence of simple flexuous trichomes on the younger branches, apex of the petioles and on the leaf abaxial surface on the main nerve and the inner most pair of primaries towards the base forming mite domatia; leaves plinervate with two pairs of secondaries; flowers (4–)5(–6) -merous, pedicels 0.7–0.9(–1.2) mm long, anthers dimorphic, in the staminate flowers opening by two broad pores; ovary in the pistillate flowers ½–2/3 inferior, (2–)3(–4) -locular.

Type:— MEXICO. Guerrero: Mpio. Atoyac de Alvarez, a 0.9 km al WNW de la desviación a La Guitarra , carretera Atoyac-Puerto del Gallo , 17°29’16’’N, 100°11’59’’W, 2430 m, 15 November 2015, (fl. ♂), de Santiago 3126 (holotype: FCME!; isotypes: CAS!, K!, MEXU!, NY!, P!, UPCB!, UEC!, UFRR!, US!). Figures 1–3 .

Shrub or tree 1.5–4 m tall, dioecious. Branches obscurely tetragonal, the bark light brown and exfoliating. Young branches, petioles, leaves abaxial surface and veins, inflorescence peduncles, bracteoles abaxial surface, and hypanthia with a dense to sparse whitish indumentum of dendritic scales, becoming glabrescent in older organs, additionally with simple flexuous trichomes 2 mm long present in the younger branches, apex of the petioles, the abaxial surface of the leaves in the axil of the primary and innermost secondary veins (forming mite domatia), and occasionally in the inflorescence peduncle, pedicels and hypanthia. Leaves isophyllous to moderately anisophyllous (in that case, the larger leaf blade and petioles up to twice as long as in the shorter leaf); petioles 1.2–5(–7.7) cm long with simple flexuous trichomes up to 2 mm long, denser towards the apex; leaf blade elliptic to oblong, (3.5–) 4.4–12.1× (0.7–) 1.8–6 cm, apex acuminate to narrowly acuminate, margin entire and ciliolate with conic trichomes 0.4–0.6(–1.2) mm long, base acute to obtuse or more rarely rounded and occasionally slightly asymmetric; venation with two pairs of secondary veins and a faint inframarginal pair, the inner pair of secondary veins diverging from the primaries 2–18 mm from the leaf base, the tertiary veins spaced 1.6–8 mm, the quaternary veins reticulate and forming areolae 0.5–1 mm wide. Inflorescence a terminal panicle, 2.2–6 cm long, pedunculate, rarely sessile, and often with accessory branches, the peduncle obscurely tetragonal, the flowers grouped in dichasia or small glomerules of 3–4 flowers, the pedicels not articulated, occasionally the pedicels of pistillate flowers with simple trichomes 2 mm long, otherwise glabrous; bracteoles early caducous, subulate, 0.9–1.2 × 0.15–0.2 mm. Flowers (4–)5(–6) merous, diplostemonous, pedicels 0.7–0.9(–1.2) mm long. Staminate flowers with hypanthia sub-hemispheric to broadly campanulate, (0.9–)2–2.4 × 2.4–2.6 mm; calyx tube 0.2–0.3 mm long, the internal lobes broadly triangular to truncate, ca. 0.3 × 0.8 mm, the external teeth broadly triangular with an tuberculate and ascending tooth, barely separating from the inner lobes; petals 1.4–1.7 × 1–1.5 mm, white, obovate, with the apex asymmetric and emarginated, the margin entire, glabrous; stamens (8–)10(–12), white, dimorphic, glabrous, the filaments 1.5–2(–2.3) mm long at anthesis slightly inflexed 7/10 from the base, the basal portion arcuate and the distal portion straight; antesepalous anthers 1.2–1.8 mm long, 0.4–0.5 mm wide and 0.3–0.4 mm thick, connective expanded downwards with two dorsal and two ventral lobes each 0.6–0.7 mm long, thecae 4-locular, straight to slightly incurved, opening by a ventrally inclined pore, 0.3–0.4 mm diam, separated by a septum proyected 0.1–0.15 mm above the rim of the pore; antepetalous anthers (0.9–) 1.1–1.6 mm long, 0.5–0.7 mm wide, 0.3 mm thick, the connective expanded downwards with a single dorsal triangular to truncate lobe, usually appresed to the filament, and two ventral lobes, 0.3–0.4 mm long; thecae 4-locular, straight to slightly arcuate, obovoid, opening by two broad pores, together 0.4–0.5 × 0.3–0.4 mm, separated by a septum 0.1–0.15 mm tall; ovary collapsed and with aborted ovules, the styloid up to 0.2 mm long and the apex slightly expanded. Pistillate flowers with and urceolate hypanthium (0.9–)2–2.4 × 2.4–2.6 mm; calyx, corolla and filaments as in the staminate flowers, anthers dimorphic and of similar size to those in the staminate flowers, but not as wide, collapsed and without obvious pores, ovary 1/2–2/3 inferior, (2–)3(–4)-locular, the style 2.4–3 mm long, stigma capitate 0.7–1 mm wide. Fruits blue when mature, fleshy, spherical, ca. 6 mm diam. Seeds numerous, ovoid, 0.8–1 × 0.4–0.5 mm on lateral view and 0.4–0.45 mm wide in dorsal view, the testa undulate-crateriform, with the cells in an irregular pattern, the anticlinal walls elevated and the periclinal walls concave.

Distribution and Ecology:— Miconia portogallensis is known only from the Sierra Madre del Sur in the Filo Mayor region south of Puerto del Gallo between the latter and the small community of Los Morros ( Figure 4 ). All the collection localities are within the municipalities of Leonardo Bravo, General Heliodoro Castillo, and Atoyac de Álvarez in the state of Guerrero. This species has been collected between 2100–2830 in forests dominated by Pinus , Abies and a mix of Pinus and Quercus on what is considered humid montane forests ( Villaseñor 2010).

Wasps of the subfamily Eumeninae have been collected visiting the flowers of M. portogallensis . Although the great majority of Melastomataceae are pollinated by bees ( Renner 1989), several species of Miconia with broad pores or slits in sections Cremanium , Chaenopleura , and Chaenanthera have been reported to be visited and potentially pollinated by other types of insects including wasps ( Renner 1989, Kriebel & Zumbado 2014, Brito et al. 2016).

Phenology:— blooming from August to February and collected in fruit from January to July.

Conservation status:— The extent of occurrence (EOO) as estimated with the geospacial conservation tool (http://geocat.kew.org), is 32,000 km 2. However, from within this area M. portogallensis has only been collected along the main road. Therefore, we consider that at this point this species falls within the Data Deficient category ( IUCN 2012).

Etymology:— The epithet portogallensis makes reference to the locality of Puerto del Gallo in the limit of the municipalities of Atoyac de Álvarez and General Heliodoro Castillo in the state of Guerrero. This place can be considered the gateway to the Filo Mayor region.

Additional Specimens examined (paratypes):— MEXICO, Guerrero. Mpio. Atoyac de Alvarez. Cerca de 1 km

de la desviación a La Guitarra , carretera Atoyac-Puerto del Gallo, bosque de Pinus , 17°29’15’’N, 100°11’39’’W, 2500 m, February 1992 (fl, ♀) ; R. de Santiago 103 ( CAS!, FCME!, K!, MEXU!, NY!, P!, UPCB!) ; ibidem, February 1992 (fl, ♂), R. de Santiago 104 ( CAS!, FCME!, MEXU!, NY!) ; ibidem, February 1992 (fl, ♂), R. de Santiago 105 ( FCME!, K!, MEXU!, NY!, UPCB!) ; ibidem, February 1992 (fl, ♂), R. de Santiago R. de Santiago 110 ( CAS!, FCME!,

MEXU!, NY!); desviación a El Iris , carretera Puerto del Gallo-Atoyac, bosque mesófilo de montaña, 17°29’26’’N, 100°12’9’’W, 2400 m, February 1992 (fl. ♂), R. de Santiago 115 ( FCME!, MEXU!, NY!) ; ibidem, December 2001 (fl, ♂), R. de Santiago 930 ( FCME!, MEXU!, NY!) ; ibidem, December 2001 (fl, ♀), R. de Santiago 931 ( CAS!, FCME!, K!, MEXU!, NY!, UPCB!) ; ibidem, December 2006 (fl, ♂), R. de Santiago 1963 ( CAS!, FCME!, MEXU!, NY!, P!,

UPCB!); A 1.5 km de la desviación a El Iris, carretera Puerto del Gallo-Atoyac, bosque mesófilo de montaña, 2280 m,

17°29’33’’N, 100°12’25’’W, July 1992 (inm. fl), R. de Santiago 170 ( FCME!, MEXU!) ; ibidem, August 1993 (inm.

fl), R. de Santiago 177 ( FCME!) ; Desviación a La Guitarra, bosque de Pinus , 2550 m, 17°29’11.5’’N, 100°11’39’’W, January 1993 (fl, ♀), R. de Santiago 174 ( CAS!, FCME!, MEXU!, NY!, P!, UPCB!) ; ibidem, January 1993 (fl, ♀),

R. de Santiago 175 (FCME!); a 0.4 km al WNW de la desviación a La Guitarra , carretera Atoyac-Puerto del Gallo, bosque de Pinus , 2530 m, 17°29’14’’N, 100°11’59’’W, December 2015 (fl, ♂), R. de Santiago 3124 ( FCME!, MEXU!, NY!) ; ibidem, December 2015 (fl, ♀), R. de Santiago 3125 ( FCME!, MEXU!, NY!) ; a 5 km al SW de Puerto del Gallo, camino Atoyac , bosque mesófilo de montaña, 2350 m, 17°29’16’’N, 100°12’10’’W, October 1983 (fl, ♀) ,

E. Martínez 5034 (MEXU!, MO); a 6 km al SW de Puerto del Gallo, bosque mesófilo de montaña, 2320 m, March

1983(fr), J. C. Soto 5140 ( ENCB!, MEXU!, MO!). Mpio. General Heliodoro Castillo. Puerto del Gallo, bosque de coníferas, 2420 m, 17°28’40’’N, 100°10’49’’W, July 1985 (fr), C. Arredondo 2 ( FCME!) ; ibidem, July 1985 (fr). V .

Valverde 15 (FCME!); a 10 km adelante de La Vuelta, camino Filo de Caballos-Puerto del Gallo, bosque de Pinus-Quercus, 2530 m, 17°28’49’’N, 100°2’14’’W, January 1983 (fr), G. Campos 526 (FCME!, MEXU!); desviación a El Edén, 8 km después de Escalerilla hacia El Gallo, bosque mesófilo de montaña, 2630 m, 17°26’59’’N, 100° 4’19’’W, May 1996 (fr), R. de Santiago 549 (CAS!, FCME!, K!, MEXU!, NY!, UPCB!); ibidem, June 1999 (fr), E. Velázquez 2196 (FCME!); aproximadamente a 1.5 km de Escalerilla hacia Puerto del Gallo, bosque mesófilo de montaña, 2700 m, 17°27’26’’N, 100°3’00’’W, December 2006 (fl, ♀), R. de Santiago 1960 (CAS!, FCME!, K!, MEXU!, NY!, P!, UEC!, UPCB!, US!); ibidem, December 2006 (fl, ♂), R. de Santiago 1961 (CAS!, FCME!, MEXU!, NY!, P!, UPCB!); Cañada al E de Puerto del Gallo, ladera oeste del cerro Teotepec, bosque mesófilo de montaña, 2960 m, 17°28’34’’N, 100°10’40’’W, June 1999 (fr), E. Domínguez 618 (FCME!); ibidem, June 1999 (fr), E. Domínguez 656 (FCME!); al SE de Puerto del Gallo, ladera oeste del cerro Teotepec, bosque mesófilo de montaña, 2480 m, 17°28’1’’N, 100°10’13’’ W, October 1999 (fl, ♂), E. Domínguez 1324 (FCME!, MEXU!); 27 km al E de Puerto del Gallo, carretera a Filo de Caballos, bosque de Pinus-Quercus, 2630 m, 17°28’N, 100°2’20’’W, August 1983 (inm. fl), P. Tenorio 1443 (ENCB!, MEXU!); El Gallo, cañada al oriente del poblado, ladera oeste del Teotepec, bosque mesófilo de montaña, 2430 m, 17°28’30’’N, 100°10’8’’W, June 1999 (fr), E. Velázquez 2133 (FCME!); aproximadamente a 3 km antes del Gallo, frente a la entrada a Las Pozas, O del Teotepec, bosque de Pinus , 2550 m, 17°27’50’’N, 100°10’W, April 1999 (fr), E. Velázquez 2018A (FCME!). Municipio Leonardo Bravo. Los Morros, bosque de Pinus - Quercus , 2100 m, 17°41’19’‘N, 99°48’22’‘W, October 2003 (fl. ♀) A. Almazan 296 (FCME!, MEXU!).

Discussion:— Miconia portogallensis is vegetatively similar to M. oligotricha given their whitish branches and leaves with dark green adaxial surface. However, M. portogallensis is clearly differentiated from M. oligotricha by the presence of long flexuous trichomes in young branches, petioles and inflorescence peduncles (vs. with the stiff, straight and spreading trichomes), and most notably by the presence of tufts of hairs in the leaf abaxial surface forming mite domatia at the union of the primary and innermost secondary veins (vs. mite domatia absent in M. oligotricha ). Additionally, the leaves of M. oligotricha are basally nerved or very shortly plinerved with short (ca. 0.15 mm long) conical trichomes on the abaxial surface, and the inflorescences rarely have accessory branches and the flowers are grouped in well defined dichasia in which the two lateral flowers have articulated pedicels (vs. leaves obviously plinerved and with long flexuous trichomes and inflorescences usually with accessory branches and flowers grouped in dichasia with short and not articulated pedicels of few-flowered glomerules in M. portogallensis ). In M. oligotricha the stamens are subisomorphic (vs. clearly dimorphic), the ovary is covered by a few glandular trichomes (vs. glabrous) and the seeds have the testa with cells in a jigsaw pattern (vs. straight). Other species of Miconia section Cremanium in the region are M. glaberrima ( Schlechtedal 1839: 421) Naudin (1850: 243) and M. rzedowskii de Santiago Gómez (2012: 144) , both lacking the characteristic long flexuous trichomes of M. portogallensis . It should be also noted that while M. portogallensis is found exclusively in the Sierra Madre del Sur, M. oligotricha is distributed in the Sierra Madre Occidental. Several specimens determined as M. oligotricha from Eastern Guerrero, Oaxaca and the Western slopes of the Sierra Mazateca in Puebla seem to belong to a still undescribed species (de Santiago unpl. data). Even if this last group of specimens is considered part of M. oligotricha , M. portogallensis and M. oligotricha are not sympatric in any portion of their distribution.

Similar mite domatia formed by trichomes and the merging point of the primary and secondary veins are also present in other Mesoamerican species of Miconia section Cremanium , most notably in M. schnellii Wurdack (1972: 203) and M. talamancensis Almeda (2000: 48) . However, these two species have perfect flowers, lack the flexuous trichomes in the stems and petioles, and are distributed farther south in Costa Rica and Panama. The presence of mite domatia can be variable within other species of Miconia , such as in M. tonduzii Cogniaux (1891: 1191) . However, the combination of characters given above seem to clearly separate all specimens with mite domatia into one entity, even if this character is not taken into account, which seems to indicate that the presence of mite domatia is fixed in M. portogallensis .

Within Mexico and Mesoamerica the following dioecious species of Miconia section Cremanium are known: Miconia alpestris Cogn. in Donnell Smith (1895: 288), from Guatemala and probably Chiapas in Mexico; M. coriacea ( Swartz 1788: 70) de Candolle (1828: 189) , from Costa Rica and disjunct in Dominica and Guadalupe in the Lesser Antilles; M. glaberrima , found from Mexico to Honduras with doubtful reports from El Salvador, Colombia, Peru and Bolivia; M. hemenostigma Naudin (1850: 230) , from México and Guatemala; M. oligotricha endemic to México; M. purulensis Donnell Smith (1895: 111) from Guatemala and adjacent Oaxaca in México; M. rzedowskii endemic to México; and M. sterilis Gleason (1946: 190) , from El Salvador. Additionally, M. vestita Almeda (2000: 51) from Costa Rica may also be dioecious given that the known specimen has flowers apparently perfect but the anthers seem to lack pollen ( Almeda 2000, 2009, de Santiago Gómez 2012). We provide a key to aid in the identification of this group of species.

Figures

FIGURE 1. Miconia portogallensis. A. Branch with infrutescence and detail of the leaf abaxial surface showing mite domatia at the base of the lamina. B. Staminate flower showing hypanthium in longitudinal section, petal of staminate flower in adaxial view, stamens, and flower at anthesis. C. Pistillate flower showing petal in adaxial view, collapsed anthers of pistillate flowers and hypanthium and ovary of pistillate flower in longitudinal section. D. Fruit. E. Bracteoles. (A, C–D, de Santiago 1961, B, de Santiago 1960, E, Almazán 296)

FIGURE 2. Seeds of Miconia portogallensis. A. Seed on lateral view. B. Detail of the testa showing the undulate-crateriform surface (R. de Santiago 549)

FIGURE 3. Miconia portogallensis. A–B. Functionally staminate flowers with Eumeninae wasp, a potential pollinator. C. Functionally staminate inflorescence in recently collected specimen. D. Detail of functionally staminate flowers. (R. de Santiago 3126).

FIGURE 4. Distribution map of Miconia portogallensis (open triangles) and Miconia oligotrica (solid triangels).