Magnolia heribertoi A.Vázquez, Rodr.

Vázquez-García, J. Antonio, Padilla-Lepe, Jesús, Gallardo-Yobal, Sergio, Rodríguez-Pérez, Ciro, García-Escobar, Alan & Muñiz-Castro, Miguel Á., 2024, Three new Mesoamerican species of Magnolia (M. sect. Talauma, Magnoliaceae) from the Chimalapas-Uxpanapa region, Mexico, Phytotaxa 652 (1), pp. 10-32 : 18

Magnolia heribertoi A.Vázquez, Rodr. -Pérez & Muñiz-Castro, sp. nov. ( Figs 6–8 )

Type:— MEXICO. Oaxaca: Mpio, Sta. María Chimalapa, ca. 7 km al S de Sta. María por la cabecera del Río Escolapa , en cañada al oeste de la vereda, 420 m ; 12 May 2011 (fl), Vázquez-García 9152 (holotype: IBUG; isotype: MEXU).

Magnolia heribertoi has similar fruit dehiscence (carpels detaching in multi-carpellate, irregular masses) to that of M. perezfarrerae ( Fig. 8 ). However, it differs from the latter in being taller (23.0–60.0 vs. 18.0–20.0 m) with narrower petioles 0.2–0.3 vs. 0.8–0.9 cm, shorter leaf blades (12.5–17.0 vs. 17.8–25.0 cm), more pairs of secondary veins (12–14 vs. 7–9), the longest peduncular internode of mature flowers is longer (22.0–23.0 vs. 14.0–15.0 mm), shorter flower buds (5.5 vs. 8.0–12.0 cm), broadly ellipsoid sepals (vs. broadly ovate), more stamens (217 vs. 175), spheroidal fruit (vs. broadly ovoid to ellipsoid) and fewer (36–46 vs. 89–92) and narrower carpels (1.1–1.2 vs. 1.4–1.5 cm) without apiculate dorsal walls.

Evergreen trees, 23.0–60.0 m tall, 30.0–120.0 cm dbh, with small buttresses, bark creamy brown, verrucose, with huaco ( Mikania sp. ) odour, inner bark yellowish; twigs with small, light-yellow lenticels, short internodes 0.4 × 0.2 cm, glabrous, green; stipules 1.5–4.6 × 0.8 cm at the base and apex 0.4 cm, pubescent, brown. Leaves 22.0–25.7 × 6.3–6.5; petioles 6.5–10.0 × 0.2–0.3 cm, finely tomentose, ribbed, green, with whitish margins; stipulate scars slightly pubescent, yellow stipular scars 6.0– 9.5 cm long along most of the petiole; leaf blades 12.5–15.7(–17.0) × 6.3–6.5(– 10.0) cm, glabrous, lustrous, elliptical, apex obtuse, base round, margin entire, emerald green; secondary veins 12–14, recurved, glabrous. Flower buds 5.5 × 6.8 cm, pubescent, broadly ellipsoid, beige; bracts 3, 5.5–5.7 × 6.2–6.5 cm, adaxial side finely pubescent, 6–8 veins, ovoidal, brown; peduncle 12.0–13.0 × 22.0–23.0 mm, pubescent, yellow, internodes 0.5–1.1 cm, green with dark spots. Open flowers 6.0–6.2 × 7.0– 7.3 cm diam., wine with white; sepals 3, 5.5–5.7 × 6.2–6.5 cm, glabrous, broadly ellipsoid, brown; external petals 3, 9.5–10.5 × 3.7–4.5 cm, glabrous, ovate, adaxial side brown and the abaxial side with purple spots; internal petals 3, 8.5–9.0 × 3.2–3.5 cm, glabrous, oblong, abaxially in the middle with purple spots; stamens 217, 1.6–2.2 × 0.4–0.7 cm, glabrous, recurved, base cuneate, apex acute, yellow with the central portion of abaxial side red; gynoecium 4.0–4.2 × 4.4–4.5 cm, glabrous, rhomboidal, with brown spots; styles 0.8–0.9 × 0.2–0.3 cm, glabrous, linear, yellow with brown to purple spots. Fruits 5.8–8.3 × 5.5–8.2 cm, spheroidal, woody, glabrescent, brown-greyish; carpels, 36–42(–46), 4.2–4.3 × 1.1–1.2 cm, glabrous, detaching in multi-carpellate irregular masses, each one is Y or V-shaped, beige; dorsal walls 1.0– 1.5 cm, ovoid with a small intermediate fissure; sidewalls 1.4–2.3 cm, yellow; small beak 0.1–0.2 × 0.2–0.3 cm, glabrous, truncate, brown; seeds 1.3–1.5 × 0.5–0.7 cm, ovate, reddish, brown sclerotesta.

Eponymy:— Named for Heriberto G. Hernández, who, in addition to Thomas Wendt, was the greatest explorer of the Selva Chimalapas and the Uxpanapa region, where this species appears to be endemic. He was also involved in collecting the species.

Distribution, ecology and ethnobotany:— Confined to Oaxaca, 350–420 m ( Fig. 1 ); frequent on slopes on deep brown soils in tropical rain forests with Hirtella triandra , Licania hypoleuca , Pouteria neglecta , Terminalia sp. , Guatteria anomala and Vatairea sp. Known locally as flor de corazón (flower of the heart) and magnolia. It has been used in medicinal beverages by local inhabitants.

Conservation status:— Rare, authors failed on two occasions to locate trees of the known populations.According to the IUCN criteria and conditions B1, B2(ab), C2(a)(i, ii) and D, this species is assessed as CR, EOO 3.5 km 2 and AOO 8 km 2. It was absent in both the Escolapa watershed and La Gloria, and only four mature trees and two young individuals were located on the way to Bolsa de Oro, surrounded by pasturelands.

Additional specimens examined:— MEXICO. Oaxaca: Santa María Chimalapa, Camino a Bolsa de Oro , 16°51’33.2”N 94°41’17.7”W, 300 m, 3 Jun 2023 (sterile), Vázquez García & Rodríguez Pérez 10321 (IBUG) ; Mpio: Sta. María Chimalapa, ca. 7 km al S de Sta María por la cabecera del Río Escolapa , en cañada al O. de la vereda ; 16°51′ N; 94°41′ W; 400 m; Aug 1986 (both fl, fr) Hernández-G. 2302 (CHAPA, LSU).

Figures

FIGURE 1. Geographic distribution of Magnolia sect. Talauma in Chimalapas-Uxpanapa region, Oaxaca and Veracruz, Mexico.

FIGURE 6. Magnolia heribertoi. A. Leaves. B. Flower starting male phase. C. Seeds. D. Top: from left to right, three sepals, three outer petals and three inner petals; bottom: stamens. E. Fruit. F. Multi-carpellate irregular mass detached from fruit axis. A, C, E and F from Hernández G. 2302; B and D from Vázquez-García et al. 9152. Photographs by A. Vázquez.

FIGURE 7. Magnolia heribertoi. A. Tree in situ on the way to Bolsa de Oro, Santa María Chimalapa, Oaxaca. B. Distal face of fruit. C. Tree with lianas. D. Juvenile plant. Photographs A, B & C by C. Rodríguez; D by A. Vázquez.

FIGURE 8. Differences between the species of Magnolia sect. Talauma with spheroid to sub-globose fruits at the same scale. A. M. perezfarrerae. B. M. lacandonica. C. M. uxpanapana. D. M. heribertoi. E. M. zoquepopoluca. F. M. yajlachhi. Photographs by A. Vázquez.