Magnolia zotictla A.Sánch., 2021

Sánchez-González, Arturo, Gutiérrez-Lozano, Marisol, Yescas, Reyna Domínguez, Hernández-Álvarez, Adriana Gisela, Ortega-Peña, A. Salomé & García, J. Antonio Vázquez-, 2021, Magnolia zotictla (Magnolia sect. Macrophylla, Magnoliaceae): a new species from the southern Sierra Madre Oriental, México, Phytotaxa 513 (4), pp. 271-281 : 272-279

Magnolia zotictla A.Sánch. -Gonz., Gut.-Lozano & A.Vázquez, spec. nov. ( Fig. 1 )

Type:— MEXICO. Hidalgo: Municipality Acaxochitlán, Zotictla , 0.3 km al SE de San Miguel del Resgate, bosque mesófilo de montaña, 1743 m, 20 ° 13’32.5”N, 98 ° 09’48”W, 5 May 2021 (fl & fr) Gutiérrez-Lozano et al. 10186 (holotype: HGOM; isotypes: ENCB, IBUG, OAX) .

Magnolia zotictla is morphologically more similar to the distant M. dealbata than to nearby M. rzedowskiana . It shares with the former habit size and large, deciduous, abaxially glaucous leaves. However, it differs from M. dealbata in having pubescent pedicels (vs. glabrescent), flowers with sepals erect (uncurled) at female phase (vs. curling outwards with petals maintaining a compact oblong conic shape), most petals strongly curled outward (vs. occasionally curling), stamens 1.3–1.8 (vs. 1.9–2.1 cm long), stigmas crowded, strongly curved outward and covering the carpels (vs. loose, slightly curved outward and exposing the carpels), young fruits velvety (vs. glabrescent), mature fruits pinkish-purplish to dark red (vs. dark greenish to yellowish), carpels densely pubescent (vs. glabrescent) and carpel beak acuminate to caudate with the stigmatic tip sometimes persistent during dehiscence (vs. acute to blunt with a deciduous stigmatic tip).

Deciduous trees, 10–25(–32) m, 10–100 cm in diameter, trunk erect and conical, crown sparse, top branched, bark scaly, fissured longitudinally and lenticels and leaf scars abundant. Stipules united 3/4 of the length of the petiole, oblonglanceolate, with acute apex, densely scattered on the abaxial side, sericeous, glabrous adaxially. Petioles 5.0–7.0 cm long, 0.4–0.6 cm in diameter. Leaves obovate, acute at the apex, auriculate or cordate at the base, adaxially glabrous and green, abaxially white-glaucous (due to their sericeous epicuticular surface) with scattered white pubescence. Leaf blades 32.8–44.4 × 19.8–26.6 cm; midvein 3.2–4.2 mm in diameter. Bracts spathaceous (2), ovate-oblong, densely sericeous on the abaxial side. Pedicel (uppermost internode) 1.1–1.8 × 1.7–1.9 cm, glabrescent and usually glaucous towards the apex, the adjacent internode glabrescent, 3.8–5.3 × 1.5–1.7 cm. Flowers terminal, solitary, hermaphrodite, white when young, cream-yellowish when mature. Sepals 3, oblong-elliptic, truncate at the base with an acute apex, greenish yellowish, glabrous and often glaucous, 14.1–18.7 × 4.4–7.1 cm. Outer petals 3, oblong-elliptical, with acute apex, abruptly attenuate at the base, white, blades glabrous, 11.4–24.1 × 5.6–11.4 cm. Inner petals 10.4–21.7 × 4.7–8.4 cm. Floral axis 6.4–7.1 cm long. Stamens 337–478, linear, creamy white, rounded to obtuse at the apex, truncate at the base. Gynoecium ovoid, yellowish, pubescent, carpels arranged in a spiral, 1.5–1.6 × 0.2–0.21 cm; carpels 89–127, flattened, white, glabrous, 1.7–1.9 × 0.3–0.4 cm ( Fig. 3 ). Polyfollicles 7.3–11.3 × 5.3–6.4, ovoid. Seeds 1–2 per carpel, 1.2–1.6 × 0.7–1.0 cm, ovoid to oblong or subpyramidal, with an obtuse base and apex and red sarcotesta. Fruit stalk 1.1–1.8 long, 1.2–1.9 cm in diameter.

* Environmental data obtained from INEGI (2005) and biotic information from Vázquez-García et al. (2013), Domínguez-

Yescas et al. (2020).

Distribution and ecology:— Distributed on the southern edge of the biogeographic province of Sierra Madre Oriental (on the border between the states of Hidalgo and Puebla). A few magnolia trees still thrive wild in ravines or hills within highly fragmented, disturbed and open cloud forest remnants. Occasionally they form small groups but mostly are isolated near crops or home orchards, among widely spaced houses and bordered by secondary cloud forest vegetation dominated by Liquidambar styraciflua Linnaeus (1753: 999 ; Altingiaceae ) and Alnus acuminata Kunth (1817: 20 ; Betulaceae ). Most Magnolia trees are close to or within the hilly villages of the Acaxochitlán Municipality, Santa Catarina, Toxtla and Zotictla, the last with three barrios: Centro, Tlaloc and Yeloxóchitl. Another population was found in the town of Ahila, Pahuatlán Municipality, Puebla. The largest population of this species was at Zotictla, 25 trees. Santa Catarina had 15, Ahila 11 and Toxtla 5.

Phenology:— During the study period, it was observed that the production of leaves begins in February, and the production of flower buds begins in the first week of March. The ripening of the fruits was observed from the end of April and the beginning of May. Falling of leaves for this species is from November to January. In M. rzedowskiana , flower buds appear at the end of April and beginning of May.

Ethnobotany:— In the ancient cultures of America and Asia, magnolias were known for their ornamental and pharmacological use, essentially to alleviate various types of human pathologies ( Pfaffman 1975, Dodd 1980, Gutiérrez-Carvajal 1993, Gutiérrez and Vovides 1997, Satyajiy et al. 2002, Vázquez-García et al. 2015). This species is known locally as magnolia, eloxóchitl or yeloxóchitl (cornflower in Náhuatl), and its showy and fragrant flowers are usually collected for sale locally. The most important use in the region is to prepare floral infusions to treat heart problems, nerve problems and scars. It is also used as an ornamental plant. A few people from Santa Catarina, Toxtla and Zotictla sell the petals largely on Sunday in the local markets of Hidalgo (Actopan, Pachuca, San Miguel Resgate and Tulancingo), Puebla (Honey, Pahuatlán), Veracruz (Poza Rica and Tuxpan), and Mexico City (Sonora traditional market). A kg of petals sells at $4–6 USD for use as infusions.

Conservation status:— Magnolia zotictla has a narrow distribution, found only in the towns of the Acaxochitlán, Hidalgo (Santa Catarina, Toxtla and Zotictla) and Pahuatlán municipalities in Puebla (Ahila). The habitat is highly fragmented and disturbed, and trees are mostly isolated. The four populations observed have fewer than 60 adult individuals in total. Only a few seedlings and juveniles were observed inside the forest ( E. Méndez, pers. comm., 6 July 2020). In addition to this, it was observed that the flowers are collected without control because they are showy and have a pleasant smell; the local people are well acquainted with this plant species but have no interest or concern for its conservation. It was observed that the trees fall easily during the hurricane season or when the wind and rain are intense. Small mammals and birds eat the seeds. Thus, it is suggested that it should be immediately listed in some risk category within the Official Mexican Standard (NOM-059-2010). According to the IUCN criteria ( IUCN 2019), the species meets four different criteria [ A2 ad, B1 ab(iii, v), B2 ab(iii), C2 a(i)] and should be assigned to the critically endangered category .

Notes:— Magnolia zotictla lacks the purple spot at the base of the petals usually found on M. dealbata and differs from M. rzedowskiana in the size of the petals, number of stamens and carpels and size of the fruits ( Table 1). The most obvious difference in flowering time is that M. zotictla begins two months earlier than the two aforementioned species. Magnolia zotictla and M. dealbata occur at different latitudes 20 ° 13’– 20 ° 16’N vs. 17 ° 18’– 17 ° 31’N and in contrasting biogeographic provinces ( Morrone et al. 2017, Domínguez-Yescas et al. 2020), the former at the southern edge of the Sierra Madre Oriental vs. the latter at the northern edge of the Sierra Madre del Sur, separated by the Trans-Mexican Volcanic Belt. The emergence of this volcanic chain may have formed a natural barrier and secured their isolation, preventing gene flow and favoring allopatric radiation of three species M. zoctictla , M. vovidesii and M. dealbata , each one now in different biogeographic provinces ( Ibarra-Martínez 2020).

Additional specimens examined:— MEXICO. Hidalgo: Municipio de Acaxochitlán, Santa Catarina town , orchard field of ornamental plants, towards surrounding mountains, 1884 m, 21°14’20.5”N, 98°10’59’’W, 5 May 2021, Hernández-Álvarez 250 ( CHAP) ; same as previous locality, near a road and stream of uninhabited land, close to disturbed mountain cloud forest, 5 May 2021, Gutiérrez-Lozano 297 ( HGOM, IBUG) . Puebla: Pahuatlán Municipality, Ahila town , ornamental Magnolia tree outside a house, bordering secondary cloud forest vegetation, 1657 m, 20°15’26.1”N, 98° 10’58.2”W, 5 May 2021, Gutiérrez-Lozano 298 ( CHAPA, IBUG) , same locality, tree close to the previous one, 5 May 2021, Gutiérrez-Lozano 298b ( MEXU, ENCB) .

Figures

FIGURE 1. Allopatric distribution of Magnolia section Macrophylla within the Mexican biogeographic provinces (Morrone et al. 2017).

FIGURE 3. Magnolia zotictla (A–C):A. Mature fruit, B–C. During and after dehiscence. Magnolia dealbata (D–F): D. mature fruit, E–F. During and after dehiscence. A–C Photographs by Arturo Sánchez. D–F Photographs by Reyna Domínguez.