Soto, Valencia-A & Soto-Arellano, 2025

Valencia-A, Susana & Soto-Arellano, Oscar Javier, 2025, Notes on Quercus salicifolia and description of a new species of Quercus section Lobatae (Fagaceae) from Mexico, Phytotaxa 681 (1), pp. 55-69 : 63-66

Quercus salasiae S. Valencia & O.J. Soto sp. nov.

Type:— MEXICO. Guerrero. Municipality Atoyac de Álvarez: 1 km antes de las Delicias, 9 August 1985, J. Ramírez Santos 71 (holotype FCME-182699!, isotype FCME-11370!) (Fig. 4).

Diagnosis:— Quercus salasiae is similar to Q. salicifolia and Q. nixoniana . From Q. salicifolia it is mainly distinguished by its shorter petioles (1.7‒3.5(‒7) vs. 2.8‒7.7(‒9.6), shorter length/width ratio (2.6‒3.2(‒3.8) vs. 3.7‒4.9), and the adaxial blade surface somewhat shining vs. dull. From Q. nixoniana it can be distinguished by its oblanceolate, obovate, elliptic to pandurate leaves vs. narrowly elliptic to lanceolate, as well as the number of secondary veins on each side of the midvein (13‒16(18) vs. 15‒23), and its way of these respect to midvein (moderately curved and ascending vs. almost straight and almost perpendicular).

Description:—Trees 15‒25(30) m tall; stems ca. 0.4 m diam., twigs 1‒3 mm diam., slightly furrowed, greyish to reddish brown, lenticels inconspicuous, glabrous; buds ovoid, 5-6 mm long, scales glossy, broadly ovate to very broadly ovate, margin moderately ciliate; stipules deciduous. Mature leaves with petioles 1.7‒3.5(‒7) × 2‒3.1 mm, glabrous, thick at the base, often depressed between the leaf base, reddish-brown basally; blades evergreen, coriaceous, oblanceolate, obovate or elliptical to pandurate 10.5‒17(‒28) × 2.8-5(‒9) cm, 2.6‒3.2(‒3.8) times longer than wider; apex acute-acuminate, tip aristate; margin entire, cartilaginous, somewhat crisped and slightly revolute; base cuneate, narrowly rounded or narrowly subcordate; secondary veins 13‒16(‒18) on each side of the midvein, moderately curved, ascending, regularly distributed (more or less regularly equidistant from each other), branching and anastomosing near the margin, with evanescent intermediates, adaxial blade surface somewhat glossy, slightly reddish-green to glaucous, midvein smooth or raised, secondary veins and veinlets concolorous or somewhat yellowish; abaxial blade surface somewhat dull, glabrous or with tufts of fasciculate shortly stipitate to sessile trichomes in the axils of the secondary veins, secondary veins slightly raised, epidermis smooth. Pistillate flowers 1‒2 at the apex of a glabrous peduncle 0.4‒1.4 cm long, stigmas 3, tomentose on the outside and rolled, forming a spiral. Fruits annual, 1‒2 at the end of a peduncle ca. 1 cm long or rarely sessile on the twigs, cupules hemispheric, rarely incipiently turbinate, 7‒10 mm tall × 10‒14.5 mm diam., margin erect, scales triangular, canescent and smooth; acorns ovoid to subspheric, 15‒30 mm tall × 10‒26 mm diam., brown, covered with a fine canescent indumentum at the apex, including 1/4‒1/3 of their total length in the cupule.

Distribution and ecology:— Mexico (Chiapas, Guerrero, and Oaxaca) ( Fig. 5 ), possibly in Guatemala. Elevation (540‒) 700‒1820 m. It occurs in pine-oak forest, oak forest and riparian forest. Associated with Quercus glaucescens Bonpland (1809: 29) , Pinus maximinoi, H.E. Moore (1966: 8) , some species of Magnolia Linnaeus (1753: 535) , and species of the family Malvaceae Jussieu (1789: 271) .

Phenology:—Flowering time is January, and fruits mature from May to September.

Conservation status:—According to the IUCN (2024) categories and criteria and the calculated value of the extent of occurrence (EOO = 91,804.781 km 2), Quercus salasiae may be considered as Least Concern (LC). However, based on the area of occupancy (AOO = 172 km 2), it may be assessed as Endangered (EN) because its area of occupancy is less than 5000 km 2. Taking into account this information, in addition to the locations of the collections that allow us to infer that the species is widely distributed throughout the Sierra Madre del Sur and the Sierra Madre de Chiapas, Mexico, and that it occurs in different environments, we propose the preliminary category of LC for Q. salasiae .

Etymology:—The specific epithet honors Dra. Silvia Hortencia Salas, who has dedicated a large part of her studies to botanical exploration in the state of Oaxaca, and who collected part of the botanical material of this species.

Common name:—Encino de castaña, Toki, encino blanco.

Additional specimens examined:— MÉXICO, CHIAPAS. Municipality Angel Albino Corzo: Paraje San Luis, Ejido Nueva Independencia, 1820 m, 5 March 1989, U. Bachem et al. 418 ( MEXU) ; Ejido Angel Albino Corzo, U. Bachem & R. Rojas 689 ( MEXU). Municipality Cintalapa: 15 km al N de Cintalapa, sobre el camino hacia Francisco I. Madero, 820 m, A. Reyez-García et al. 1472a ( MEXU). Municipality La Concordia : Paraje La Naranja , Predio particular El Horizonte, 740 m, 16 May 1989, U. Bachem & R. Rojas 934 ( MEXU). Municipality Villacorzo: Paraje “El Alto”, ejido Plan de Ayala , 1020 m, 27 July 1998, R. Ramírez & J. L. Campos 20 ( MEXU). GUERRERO. Municipality Acatepec: Comunidad de El Fuereño , 1180 m, 27 October 2012, Borda-Niño 28, 27 ( MEXU). Municipality Atoyac de Álvarez : 2 km adelante de la desviación a El Edén sobre la carr. Atoyac a Puerto del Gallo , 1000 m, 3 May 1985, V. C. Aguilar 637 ( MEXU) ; 1 km al norte del Río Santiago, 920 m, C. Arrendondo 49 ( FCME) ; 2 km adelante de San Francisco del Tibor, rumbo a la Remonta, 810 m, 7 May 1984, R. M. Fonseca 574 ( FCME) ; 4 km adelante de El Paraíso, rumbo a Atoyac, por el camino a Río Verde, 1000 m., 26 July 1984, R. M. Fonseca 697 ( FCME) ; between Río Verde and El Paraiso, a short dirt road (ca. 5 km) off the road between El Paraiso and Atoyac, 1040 m, 23 May 1987, J. S. Miller & G. Campos 2953 ( MEXU) ; Ejido El Porvenir, 810 m, 23 March 1986, G. Matus 19 ( INEGI) ; alrededores del

FIGIURE 4. Quercus salasiae . A. Holotype.

FIGIURE 4. B. Close-up of the holotype. Photo by Gabriela Flores Valencia.

poblado “El Porvenir”, 1330 m, 9 July 1985, A. Nuñez 1201 ( MEXU) ; 2 km sobre la desviación a El Porvenir, carretera Atoyac-Puerto del Gallo , 900 m, J. Ramírez 45 ( FCME) ; Puerto del Gallo , 9 July 1985, J. Ramírez s.n. ( FCME) ; 15 km al NE de El Paraiso , 1100 m, 19 August 1985, J. C. Soto & S. Román 10110 ( MEXU) ; 10 km al NE de El Paraiso, hacia Puerto del Gallo, 950 m, S. Valencia 466 ( FCME). Municipality Ayutla de los Libres: Tepetates, 900 m, 16 May 2006, J. Vázquez 38 ( FCME). Municipality Chilpancingo de los Bravo: Los Cajones, 15 January 1989, L. Rodríguez 238 ( FCME). Municipality Coyuca de Benítez : Ejido Las Compuertas, 1104 m, B. E. Carreto 1357 ( FCME) ; Hierba Santa, La Agüita, 895 m., 17 December 2013, E. González 12-02527-01 ( FCME). Municipality General Heliodoro Castillo: El Ranchito, camino Atoyac de Alvarez a Filo de Caballo, 115 m, 17º23’39”N, 100º11’49”W, 11 July 2006, J. L. Contreras 8409 ( FCME, HUAP). Municipality Mártir de Cuilapan : San Marcos, Oacotzingo, Cerro de La Cruz , 690 m, 17º54’39.7”N, 99º28’07.2”W, 21 October 2003, E. León et al. 555 ( FCME). Municipality Petatlán: El Rincón, 1100 m, 17°39’12”N, 100°55’17”W, 22 January 2010, DIAAPROY S. A. DE C. V. s.n. ( MEXU) ; El Jilguero, 2.2 km al OSO, faldas del Cerro El Jilguero, 1253 m, 17º35’49”N, 101º03’26.8”W, 4 May 2008, F. Madariaga 881 ( FCME). Municipality San Luis Acatlán: 20 km al N de Mishuiclan, 29 May 1983, J. González & J. Castañeda s.n. ( MEXU). Municipality: Técpan de Galeana: Bajos de Balzamar , 1060 m, 17°36’22.2”N, 100º 47’17.12”W, 27 July 2006, M. Hernández 133 ( FCME), 29 September 2006, M. Hernández 208 ( FCME), 29 September 2006, M. Hernández 278 ( FCME) ; Km 35, antes de llegar a la Loc. La Piedra , A. Hernández 701 ( HUAP) ; El Plato, 800 m., Hinton et al. 14363 ( CHRB, MEXU) ; Bajos de Balsamar , 1000 m, 27 June 2002, R. Mayorga 2059 ( FCME) ; La Guayabera, 26 km al NE de Coyuquilla, J. C. Soto et al. 12228 ( MEXU), 12235 ( MEXU). Municipality Tlacoachistlahuaca: Tierra Colorada, 16º57’22”N, 98º16’39”W, 8 October 2013, G. Castro 320473-03 ( FCME). OAXACA. Municipality San Ildefonso Villa Alta : Santa María Temaxcalapa , 1400 m, J. Ruiz 43 ( INEGI). Municipality San Juan Cotzocón: Divina Flores (Buenos Aires), 500 m, 14 april 2007, J. Zuñiga R. 73352a ( INEGI). Municipality San Juan Mazatlán: Lomas de Santa Cruz , 600 m, 11 april 2007, J. L. López 73570 ( INEGI). Municipality Santa María Ipalapa: El Limón (El Drago), R. Castro 75702 ( INEGI). Municipality San Miguel del Puerto. Distrito de Pochutla , Finca Montecarlo, 950 m, 15º52’24”N, 96º0’20”N, 30 April 2001, A. Saynes 2067 et al. ( FCME, MEXU) ; F. López 95 (MEXU); 600 m LR al NE del rancho San Agustín. Rumbo a el Encinal, 880 m, 15º59’44.4”N, 96º6’6.7”N, 4 June 2002, A. Saynes 2957 ( FCME) ; 400 m al N de la Finca Montecarlo, al lado de la brecha a Las Lobas, 990 m, 15º59’49.2”N, 96º6’37.5”N, 17 May 2003, S. H. Salas et al. 4986 ( FCME, MEXU), 17 May 2003, S. H. Salas 4987 ( FCME, MEXU). Municipality Santiago Lachiguiri: Santa Isabel de la Reforma (El Pico), 930 m, 12 April 2007, A. Alonso 73775 ( INEGI). Municipality Santiago Tetepec: Ocotlán de Juárez, J. Ruiz 7 ( INEGI). Municipality Santiago Yaveo: Cerro Monte Negro, 540 m, 6 June 2007, J. C. Calvillo 72290 ( INEGI). Casa de Piedra, J. C. Calvillo 72504a ( INEGI). Municipality Zimatlán de Álvarez : Rumbo a Tlacuache, 19 March 1997, M. Velasquez 12 ( INEGI) .

Notes:— Quercus salasiae can be confused with Q. salicifolia and Q. nixoniana with which it can share habitat on the Pacific slope of the Sierra Madre del Sur. Table 1 shows the main characteristics that allow these species to be distinguished.

In most fertile specimens the fruit cup has a hemispherical shape, however, in the specimen from the state of Guerrero, collected by Soto & Román 10110, the fruit cup is turbinate.

Figures

FIGURE 5. Geographical distribution of Quercus salasiae.