Symplocos nigridentata L.M.Kelly & Almeda, 2016

Kelly, Lawrence M., Almeda, Frank & Fritsch, Peter W., 2016, A taxonomic revision of Mexican and Central American Symplocos (Symplocaceae), Phytotaxa 264 (1), pp. 448-450 : 448-450

18. Symplocos nigridentata L.M.Kelly & Almeda , sp. nov. Type :— MEXICO. Oaxaca: Dist. Villa Alta, 28 km al SW de Talea, 2850 m, [17°16′05″N, 96°20′50″W], 19 April 1982, R. Cedillo T. et al. 1269 (holotype MEXU!, isotypes CAS!, F!, MO!, NY!)

Diagnosis: Distinguished from all other species of Symplocos ser. Symplocos by the combination of crenate-denticulate leaf margins with black, persistent, sharp, narrowly conical glands ca. 0.5 mm long; lanceolate-ovate, sericeous calyx lobes; and small, pubescent fruits.

Shrubs 1.5–3 m tall or trees 4–10 m tall; juvenile branchlets and vegetative buds sericeous, trichomes 0.1–0.5 mm long, white. Petioles 4–11 mm long; leaf blades bicolorous, elliptic to broadly elliptic or oblong, 5.5–8.5 × 2.3–4 cm, subcoriaceous, abaxially subglabrous to sparsely pilose or appressed-pilose, sparsely to densely strigose along midvein, adaxially glabrous, secondary veins ± adaxially impressed, base obtuse to rounded or occasionally acute, margins crenate-serrulate with black (brown when young), persistent, sharp, narrowly conical glands ca. 0.5 mm long, apex acuminate. Inflorescences racemes or spikes 1.1–1.7 cm long, 5–9-flowered; peduncle absent; rachis 3–6 mm long, sericeous, 0.1–0.5 mm long; bracts caducous, ovate, 1‒2 × 1‒1.5 mm, sericeous, margins ciliate; bracteoles caducous, 2–3, ovate, 1.5‒2 × 1‒1.5 mm, sericeous, margins ciliate; pedicels 0–1 mm long. Hypanthium densely sericeous. Calyx lobes 5, lanceolate-ovate, 2–3 × 1.5–2.5 mm, moderately sericeous, margins ciliate. Corolla pink or reddish pink, 5-lobed, 8–10 mm long; tube 3–4 mm long; lobes adnate to filament tube for 4–5 mm, oblong, glabrous. Stamens 3- or 4-seriate; filament tube 4–6 mm long, distinct portions of filaments 1–2.5 × 0.25–0.5 mm. Disk pilose; style 6–7 mm long, sparsely pilose basally; stigma irregularly lobed. Fruits green maturing to dark bluish purple, ellipsoid, 8–10 × 4–6 mm, sparsely to moderately pilose or appressed-pilose, apex acute with calyx lobes forming a conical beak; disk convex, covered by calyx lobes; endocarp 3-locular, perimeter rounded.

Vernacular name —None.

Illustration — Figure 24 .

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A TAXONOMIC REVISION OF SYMPLOCOS

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Photographic image — Figure 1g .

Phenology —Flowering January through April and August through October; fruiting August and November.

Distribution and habitat —Endemic to Mexico (Oaxaca), in Quercus - Pinus forests and cloud forests at 2500–3000 m elev. Figure 16 .

Conservation status — Symplocos nigridentata is restricted to a narrow elevational belt in the mountains northeast of Oaxaca City. None of the known populations occur in a protected area. The EOO is 1096 km ² and the AOO is 56 km ². Threats of deforestation in the region indicate a projected decline in the area, extent, and quality of habitat. We assign a classification of Endangered (EN): B2ab(iii) to this species.

Discussion —This new species is recognized by the following combination of characters: crenate-denticulate leaf margins with black, persistent, sharp, narrowly conical glands ca. 0.5 mm long; lanceolate-ovate, sericeous calyx lobes; and small, pubescent fruits. Furthermore, the fruits, although not commonly collected, consistently have three locules with only one locule fertile at maturity. Plants that were annotated by us prior to 2008 as Symplocos speciosa are referable to S. nigridentata .

Paratypes — MEXICO. Oaxaca: Comaltepec, immediately to the right of Hwy 175, just beyond the first major switchback on descent from Mirador below Cerro Humo Chico , Quebrada of Río Cerro Pelón , 2750 m, 17°35′15″N, 96°31′30″W, 1 November 1993, Boyle & Massart 2486 (CAS!, MEXU!, MO!) ; NW slope of Cerro Humo Chico, 43 km N of Ixtlán de Juárez jct. on rd to Valle Nacional , 2870 m, [17°33′33″N, 96°31′05″W], 9 November 1983, Breedlove & Almeda 59966 (CAS!, MEXU!, NY!) ; 35 km N of Ayutla along rd from Mitla to Choapam, N slope of Cerro Zempoaltepetl , 2470 m, [17°10′42″N, 96°00′35″W], 17 April 1988, Breedlove & Bartholomew 66870 ( CAS!) ; W side of Cerro Humo Chico , 2740 m, [17°34′53″N, 96°31′04″W], 29 October 1991, Breedlove & Mahoney 72302 ( CAS!) ; N side of Cerro Zempoaltepetl , 2700 m, [17°10′51″N, 96°00′26″W], 1 November 1991, Breedlove & Mahoney 72483 ( CAS!) ; Ixtlán, a 500 m al N de la desviación a San Pedro Yolox , 2700 m, [17°34′41″N, 96°30′36″W], 1 July 1982, Cedillo T. & Torres 1579 (CAS!, F!, MEXU!, MO!, TEX!) ; Yolox, Sierra de Juárez, Cerro Pelón , cerca de la desviación a Yolox , 2800–2900 m, [17°34′42″N, 96°30′40″W], 2 October 1993, Cházaro B. et al. 7118a (MEXU!, NY!) ; San Felipe Usila , 8.2 km en línea recta al S de Santa Cruz Tepetotutla, 2670 m, 17°40′03″N, 96°34′48″W, 27 February 1994, Gallardo H. et al. 949 ( MEXU!) ; San Felipe Usila , 8 km en línea recta al S de Santa Cruz Tepetotutla, 2500 m, 17°39′56″N, 96°33′36″W, 2 April 1994, Gallardo H. et al. 1027 ( MEXU!) ; Ixtlán, Mpio. Ixtlán de Juárez, 2.5 mi S of ruta nacional 175 from a point a few km N of turnoff to San Juan Evangelista Analco on timber rd to Ixtlán de Juárez , 2880 m, 17°24′N, 96°29′W, 24 April 1986, Gereau & Martin 1962 (CAS!, MEXU, MO) ; vicinity of Cerro Zempoaltepetl, E slopes at Patio de Arena ca. 5 km E of summit, 2800 m, [17°07′48″N, 95°59′27″W], 8 August 1950, Hallberg 827 ( MEXU!) ; 2 km E of Valle Nacional – Ixtlán Hwy, along the rd to Zoogochi , 20 km N of Ixtlán de Juárez (by hwy), 2971 m, 17°24.703′N, 96°29.900′W, (17°24′42″N, 96°29′53W ″), 11 January 2003, Kelly et al. 1305 (CAS!, MEXU!, NY!) ; 3 km E of Valle Nacional – Ixtlán Hwy, along the rd to Zoogochi , 20 km N of Ixtlán de Juárez (by hwy), 2960 m, 17°24.177′N, 96°29.867′W, (17°24′10″N, 96°29′52″W), 12 January 2003, Kelly et al. 1306 (CAS!, MEXU!, NY!) ; 3.5 km E of Valle Nacional – Ixtlán Hwy, along the rd to Zoogochi , 20 km N of Ixtlán de Juárez (by hwy), 2952 m, 17°24.150′N, 96°29.688′W, [17°24′04″N, 96°29′42″W], 12 January 2003, Kelly et al. 1307 (CAS!, MEXU!, NY!) ; Ixtlán, Sierra de Juárez, ruta 175 Tuxtepec a Oaxaca , cerca la base de Cerro Pelón , 2750 m, [17°32′50″N, 96°30′56″W], 13 September 1982, Lorence & Torres 4002 (CAS-2!, F!, MEXU!, MO!, NY!) ; Cerro Humo Chico, Comaltepec, Ixtlán , [17°34′24″N, 96°30′07″W], 6–7 April 1967, MacDougall s.n. ( US!) ; Cerro Humo Chico, Comaltetepec, Ixtlán , 3000 m, 29 March 1969, MacDougall s.n. ( NY!) ; Ixtlán, Mpio. Yolox, 8 km E of Yolox on rd between Yolox and Hwy 175, 2900 m, [17°35′N, 96°31′08″W], 13 April 1981, Martin 529 (CAS!, MEXU!, MO!) ; Ixtlán, Mpio. Atepec, along Hwy 175 near Llano de las Flores , 3000 m, [17°26′58″N, 96°30′46″W], 24 March 1983, Martin 672 (CAS!, MEXU!, MO!, US!) ; Sierra de Juárez, Llano de las Flores , [17°26′42″N, 96°30′06″W], 3 January 1960, Miranda 9236 ( MEXU!) ; Sierra de Juárez, parte alta de la brecha 290, Macuiltianguis , 2950 m, 20 March 1980, Pérez P. B 45 ( MEXU!) ; Cerro Pelón, 48 km al N de Ixtlán, carretera a Tuxtepec , 2850 m, [17°35′08″N, 96°30′24″W], 11 September 1976, Rzedowski 34102 (MEXU!, US!) ; Ixtlán, above Ixtlán de Juárez on the Tuxtepec Rd , [17°20′42″N, 96°30′17″W], 30 March 1966, Smith & Tejeda 4484 (MEXU!, US!) ; Ixtlán, Comaltepec, El Mirador , 1.8 km al N de la entrada a San Pedro Yolox , carretera Oaxaca–Tuxtepec , [17°34′44″N, 96°30′26″W], 27 August 1986, Torres C. & Cortes 8722 (F!, MEXU!, MO!) .

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Figures

FIGURE 1. Flowers of some species of Mexican and Central American Symplocos. a. S. longipes (photograph by Victor Steinman). b. S. austromexicana. c. S. breedlovei. d. S. coccinea. e. S. costaricana (photograph by Daniel Solano). f. S. hartwegii. g. S. nigridentata. h. S. povedae.

FIGURE 16. Geographic distribution of Symplocos hartwegii, S. hintonii, and S. nigridentata.

FIGURE 24. Symplocos nigridentata. a. Branchlet with inflorescences. b. Leaf blade margin. c. Inflorescence with flower buds. d. Flower. e. Corolla opened with attached stamens. f. Disk, style, and stigma. g. Fruit. (a–f drawn from G. Martin 672, MEXU; g drawn from B. Hallberg 27, MEXU.)