Ilex montebellensis Lozada-Pérez, 2019

Lozada-Pérez, Lucio, 2019, A new species of Ilex (Aquifoliaceae) from Mexico, Phytotaxa 409 (5), pp. 296-300 : 296-297

Ilex montebellensis Lozada-Pérez , sp. nov. ( Fig. 1 ).

Type:— MEXICO. Chiapas: Mpio. La Trinitaria, Colonia Cuauhtémoc , 16°06’35” N, 91°37’1.5” W, 1450 m.a.s.l., June 25th 1984, Méndez 7739, female, fl, fr. (holotype: XAL! ; isotype: MEXU! , MO! ).

Ilex montebellensis is morphologically similar to I. tectonica Hahn (1988: 733) , but differs in having larger leaves, 9.0 ‒ 22.0 × 4.0 ‒ 9 cm (versus 7 ‒ 10 × 3.5 ‒ 4.5 cm), petioles 1.5 ‒ 4.0 cm (versus 0.4 ‒ 0.8 cm), male inflorescences in fasciculate dichasia (versus simple dichasia), fruits with hard mesocarp (versus mesocarp fleshy) and a dorsally smooth pyrene (versus striated).

Trees, 10-20 m tall, dioecious, with glabrate branches turning black when they wither; stipules 0.5 × 0.5 mm, triangular, glabrate, petioles 1.5 ‒ 4.0 × 0.3 cm, glabrate. Blades 9.0 ‒ 22.0 × 4.0 ‒ 9 cm, elliptic, oblong-elliptic, rarely obovate, the apex short, acute to acuminate, the base rounded, seldom obtuse, the margin entire, undulate when withered, the midvein adaxially sunken and protruding abaxially, with evident secondary and tertiary veins protruding adaxially, the secondary veins evident abaxially, glabrate on both surfaces. The male inflorescences are axillary fasciculate cymes, the peduncle reduced, 1 ‒ 3 mm long with up to 5 secondary branches, the rachis 1 ‒ 10 mm long, glabrate or puberulent, the secondary rachis 5 ‒ 25 mm long, glabrate or puberulent, each branch ending in dense dichasia resembling flower heads, the pedicels 2.5 ‒ 3.5 mm long, glabrate or puberulent; the bracts 1.2 ‒ 1.5 × 1.0 mm, triangular, glabrate, with bracteoles similar to the bracts but smaller. Flowers tetramerous, with deltoid calyx lobes, 0.7 ‒ 0.9 × 0.9 × 1.0 mm, the margin ciliolate, glabrate or puberulent; corolla white, the petals oblong to oblong-elliptic, concave, 1.7 ‒ 2.0 × 1.2 ‒ 1.4 mm, the apex rounded, the margin ciliolate, glabrate and fused at the base forming a tube of 0.4 ‒ 0.5 mm long; the stamens fused with the tube, alternate with the petals, the filaments 1.1 ‒ 1.3 mm long, with ovoid anthers, 0.7 ‒ 0.8 mm long, the pistilodium conical, 1 mm long. The female inflorescences are umbelliform or fasciculate cymes, axillary, the peduncle 1.0 ‒ 1.5 cm long, puberulent or glabrate, the secondary axes 1.0 ‒ 1.5 cm long, glabrate or puberulent, each branch with terminal dense dichasia resembling flower heads, the pedicels 3 ‒ 4 mm long, glabrate, with bracts and bracteoles similar to those in the male inflorescences but smaller. Flowers tetramerous, the calyx lobes broadly ovate, 0.5 × 1.2 ‒ 1.4 mm, the apex obtuse, the margin ciliolate, dorsally glabrate or puberulent; corolla white, the petals oblong to oblong-elliptic, concave, 2.0 ‒ 2.2 × 1.8 ‒ 2.0 mm, the apex rounded, the margin ciliolate, glabrate, fused at the base forming a tube, 0.8 mm long; staminodes alternate to the petals with laminar filaments, 0.5 ‒ 0.6 mm long, with ellipsoid anthers 0.9 ‒ 1.0 mm long, with some basal trichomes; ovary ovoid, 1.0 × 1.5 mm, glabrate, the stigma capitate, ca. 10 mm diameter. Fruits drupaceous, globose, 4 ‒ 5 mm diameter, green, glabrate, calyx and stigma persistent; pyrenes abaxially smooth.

Etymology: ―Name for the Lagunas de Monte Bello National Park, located on the border with Guatemala, where most specimens used for the description of this species were collected.

Distribution and habitat: ―Known only from the southeastern region of Chiapas, Mexico, on the border with Guatemala, which is part the physiographic region called Sierra de Chiapas y Guatemala ”, elevation 900 ‒ 1600 m. The habitat is cloud forest with Liquidambar ( Altingiaceae ), Magnolia ( Magnoliaceae ), Quercus ( Fagaceae ), Sterculia ( Malvaceae ), Ulmus ( Ulmaceae ), Vochysia ( Vochysiaceae ) and less frequently in tropical rain forest.

Phenology: ―Flowers January-October, fruits June.

IUCN Red List category: ―The cited specimens have been collected since 1973, mainly in the vicinity of the Lagunas de Monte Bello, where the only population with less than 10 individuals can be found. According to the established criteria of IUCN (2015), the status of the new species would be critically endangered (CR).

Additional specimens:— MEXICO. Chiapas: Municipio Ocosingo, Comunidad Lacandona de Nahá , 16 59 N, 91 36 W, 900 m elev., 21 May 1994, Durán & Levy 180, male, fl. ( MEXU) ; Municipio La Trinitaria, east of Laguna Tziscao, Monte Bello National Park , 16°04’43”N 091°37’54”W, 1300 m elev., 23 January 1973, Breedlove & Smith 32248, male, fl. ( CAS, MEXU!, MO) ; east of Laguna Tziscao, Monte Bello National Park , 16°04’43”N 091°39’32”W, 1300 m elev., 13 May 1973, Breedlove 35249, male, fl. ( CAS, MEXU!, MO) ; 4 km east of Laguna Tziscao near Dos Lagos , 16°05’35”N 091°38’12”W, 1450 m elev., 19 October 1974, Breedlove 38921, male, fl. ( CAS, MEXU!, MO) ; a 100 m al norte del mirador de Lago Tziscao , 16 05 34, 91 40 09, 1530 m elev., 19 May 1995, Mejía & Luna 255, male, fl . ( CH!, MEXU!).

Notes: ―With the description of I. montebellensis , the presence of I. mitis , described from Africa, is eliminated from Mexico. This name has been found in several of the specimens cited in the MEXU, MO and XAL, and the author of these determinations is unknown. The difference between both species in noteworthy, especially the size of the petioles, leaves and type of inflorescence. In I. montebellensis , petioles are 1.5 ‒ 4.0 cm long, leaves are 9.0 ‒ 22.0 × 4.0 ‒ 9 cm, and inflorescences are compound cymes with dense flowers resembling heads on the terminal branches. On the other hand, I. mitis has petioles 0.4 ‒ 0.8 cm long, leaves 7.0 ‒ 10.0 × 3.5 ‒ 4.5 cm and simple cymes with 3–7 flowers. In addition, the species here described is dioecious, whereas the African species is polygamodioecious.

This new species is also probably related to I. belizensis Lundell (1937: 217) and I. tectonica , both Mesoamerican species sharing the area of distribution and belonging to the I. guianensis ( Aublet, 1775: 88) Kuntze (1891: 113) complex ( Hahn 1996). These species also share an entire leaf margin, but they differ in smaller petioles and leaves. On the other hand, I. belizensis has articulate pedicels and ovoid or ellipsoid, larger fruits, 6 ‒ 7 mm long. In I. tectonica , the abaxial veins of the leaves are yellow, the fruits are ovoid, 5 ‒ 6 mm long, red, with a fleshy mesocarp and abaxially striate pyrenes. In addition to I. guianensis , this complex also includes I. skutchii Edwin ex Dudley & Hahn (1996: 181) , making 12 Mesoamerican species that have entire leaf margins.

Figures

FIGURE 1. Ilex montebellensis. A. Male branch. B. Male flowers buds and anthesis. C. Male flower. D. Trichomes at the base of the anther. E. Female branch. F. Female flowers. G. Female flower. H. Trichomes at the base of the anther. I. Fruit with calyx and stigma. J. Pyrene.A–J Drawn by Ericka B. Cortez.