Magnolia claudiae Archila, Tribouillier & A.Vázquez, 2023

Archila, Fredy, Tribouillier-Navas, Erick, Medeiros, Alexandre Da Silva, Muñiz-Castro, Miguel Á. & Vázquez-García, J. Antonio, 2023, The tulip Magnolia (Magnoliaceae), an endangered new shrubby species endemic to Baja Verapaz, Guatemala, Phytotaxa 629 (1), pp. 85-92 : 86-90

Magnolia claudiae Archila, Tribouillier & A.Vázquez sp. nov. ( Figs 1–3 )

Type:— GUATEMALA. Baja Verapaz: La Unión Barrios , Don Nery Falls , 15º10´39´´N, 90º13´22´´W, 1500 m, 9 May 2018, growing inside the waterfall, Archila & Tribouillier MG-111 (holotype: BIGU ; isotype: IBUG) .

Magnolia claudiae is most similar to M. archilana A.Va ́zquez, Tribouill. & Véliz in Vázquez-García et al. (2019: 222) in leaf size and texture and glabrous fruits, but differs mainly in its shrubby habit, <3.0 m tall (vs. trees 8.0–14.0 m); shorter, thinner terminal twigs, 0.5–1.0 × 0.4–0.6 cm (vs. 1.1–1.4 × 0.7–0.8 cm); longer petioles, 2.5–3.2 cm (vs. 2.0–2.2); leaf blades broadly elliptic and glabrous (vs. broadly obovate and densely ferruginously pubescent); leaf apex emarginate to obliquely blunt (vs. round and slightly apiculate); young leaves reddish (vs. dark green); longer peduncular internode 5.0–6.0 (vs. 3.0–3.4); smaller flower diameter 13–14.0 cm (vs. 20.0–22.0 cm); smaller sepals 5.0–5.2 × 2.0–2.2 (vs. 7.5–7.8 × 3.5–4.0 cm); smaller petals 6.0–6.2 × 4.2–4.4 cm (vs. 8.3–8.5 × 5.5–5.8 cm); purple staminophore (vs. reddish); more numerous stamens 145–150 (vs. 72–76); smaller seeds, 0.55–0.65 × 0.4–0.5 cm (vs. 0.8–1.0 × 0.7–0.8); shorter mature polyfollicles 4.8–4.9 × 2.2–2.4 cm (vs. 7.0–7.5 × 3.4–3.6 cm); and more numerous carpels 50–52 (vs. 34–40) ( Table 1 ).

Evergreen shrubs, 3.0–5.0 m, 18–20 cm dbh, bark smooth; shoots with ferruginous orange pubescence; terminal twig internodes 0.5–1.0 × 0.4–0.6 cm. Leaves petiolate; stipules 9.5–10.0 × 1.0– 1.2 cm, glabrous, pale pink; petioles 2.5–3.2 × 0.4–0.5 cm, pubescent when young, glabrous when mature, ribbed; leaf blades 12.0–17.0 × 8.0–10.0 cm, broadly elliptic to suborbicular, when young with apical pubescent but becoming glabrous at maturity and apex changing to obliquely obtuse, obtuse or truncate, with 19–20 veins secondaries per side. Adult leaves dark green, shiny, glabrous adaxially and abaxially. Flowers solitary, 5.0–5.5 × 13.0–14.0 cm; peduncle 5.0–6.0 cm long, covered with microscopic ferruginous pubescence to about 80%, 20% with glandular-warty texture; flower buds ovate, glabrous, green with conspicuous veins; spathaceous bracts 2, the outer smooth (rough when dry), green, 7.0–8.3 × 5.0– 5.5 cm, the internal 4.5–5.0 × 4.5–5.0 cm, ovoid, with apical pubescence; flower chamber (in the form of a tulip flower), not opening as in the rest of the species of the M. section Magnolia species in Guatemala; sepals 4, light green in flower bud (anthesis), grey at maturity, oblong with the rounded apex, with prominent and visible ribs 5.0–5.2 × 2.0– 2.2 cm; petals 4–5, obovate, apically round, 5.5–6.2 × 4.2–4.4 cm; staminophore cylindrical, inversely trapezoidal, dark purple; stamens 145–150, 9.0–10.0 × 0.5–0.7 mm, each white stamen with purple base and apex, linearly curved, apically acuminate; gynoecium with 50–52 carpels, glabrous, with the base slightly, microscopically pubescent, the stigma brown, geniculate, with a tentacular, dorsally irregular corrugated. Fruits 4.8–5.0 × 2.0– 2.2 cm, green, glabrous, ovatepyramidal; basal follicles 1.8–2.0 × 0.5–0.6 cm, obtrullate, dorsal wall with two keels that run from the distal to the proximal part, apex truncate. Seeds red, 5.5–6.5 × 4.0–5.0 mm, obliquely orbicular with orange reddish sarcotesta.

Distribution, habitat and phenology:— Known from three populations, all associated with micro-watersheds and waterfalls with exposed rocks, in cloud forests in the Department of Baja Verapaz. Observed (but not collected) at Biotopo del Quetzal waterfalls and Los Ranchitos, a private protected area and waterfalls ( Fig. 4 ). Flowering May– September.

Eponymy and ethnobotany:— Dedicated to Claudia Cortez de Archila , co-collector of the species. Known by residents of the area as magnolia tulipán and used as a charcoal source.

Conservation status:— Endemic to Baja Verapaz and known from only three populations near the type locality with a total of 20 adult trees; it should become a target for conservation efforts. Two populations are not in protected areas and are exposed to several threats. Like many other Neotropical Magnolia species ( Rivers et al. 2016, Vázquez-García et al. 2013 a, Archila 2022) M. claudiae is highly threatened, the known extent of occurrence (EOO) is only 23.5 km 2 and its known area of occupancy (AOO) is only 16 km 2. According to the IUCN Red List criterion B1 (EOO <100 km 2) and conditions ab(iii) ( IUCN 2022), the species could be considered critically endangered (CR). In addition to its rarity, narrow distribution, and severe habitat fragmentation (condition a), this species experiences a continuing decline observed and projected in area and quality of habitat (condition b(iii)). We could not find seeds for propagation. Being used by the inhabitants for charcoal endangers it in the forest from which the holotype was obtained. Demographic studies are required to determine the number of and size of each population.

Additional specimen examined:— GUATEMALA. Baja Verapaz: Chilascó Waterfall, 2000 m, 15º09'10'' N, 90º07'27'' W, May 7, 2021, Archila & Tribouillier MG-112 (BIGU).

Figures

FIGURE 1. Magnolia claudiae. A. Flower at anthesis, female phase. B. Dissected flower, sepals, petals, peduncle with stamens, and gynoecium. C. Polyfollicle. D. Branch with leaves. E. Leaf base. F. Emarginate leaf apex. Illustrated by A. da Silva Medeiros.

FIGURE 2. Magnolia claudiae. A. Juvenile with reddish leaves and red erect stipule. B. Flower at anthesis, female phase. C. Dissected flower. D. Polyfollicle (fruit).

FIGURE 3. Magnolia claudiae, holotype (BIGU).

FIGURE 4. Map of Magnolia claudiae and morphologically similar and geographically nearby species.