Magnolia pastorcortesii A.Vázquez & D.L. Kelly, 2022

Vázquez-García, J. Antonio, Kelly, Daniel L., Mejía-Valdivieso, Darío A., Morales, Wilson, Dahua-Machoa, Alex, Vega-Rodríguez, Hermes, Peña, Alondra Salomé Ortega, Padilla-Lepe, Jesús & Muñiz-Castro, Miguel Á., 2022, Magnolia (Magnoliaceae) in Honduras: a synopsis with six new taxa, Phytotaxa 570 (2), pp. 109-149 : 129-133

Magnolia pastorcortesii A.Vázquez & D.L. Kelly , sp. nov. ( Figs 12–15 )

Type:— HONDURAS. Depto. Cortés: Parque Nacional Cusuco, Sierra del Merendón , W. of San Pedro Sula , in midaltitude broadleaved forest ca. 1350 m, 1 Aug 2008 (fl, fr), Kelly & Cortés 12106 (holotype: TCD!; isotypes: BM!, IBUG!, TEFH!) .

Magnolia pastorcortesii shares with M. guatemalensis subsp. guatemalensis the broadly obovate leaves, but it differs in having smaller and adaxially non-shiny leaves, (9.4–)12.0–14.1 × (5.6–)6.6–8.3 vs. 12.0–16.0 × 5.5–8.5 (–11.0) cm, less numerous lateral veins per side, 10–11 vs. 12–13, smaller flowers, 5.5–6.5 vs. 14.0–16.0 cm in diam., and fewer stamens, 38–42 vs. (61–)78–80(–97) and carpels, 20–22 vs. 34–38.

Trees 14.0–15.0 m tall; bark finely and shallowly fissured, slash yellowish, darkening to orange-brown; twig internodes 0.8–1.5 × 0.3–0.4 cm, glabrous to glabrescent; stipules free from the petiole. Leaves petiolate, petioles 2.0–2.8 × 0.2–0.3 cm, without a stipular scar, glabrous, laminas (9.4–)12.0–14.1 × (5.6–) 6.6–8.3 cm, broadly obovate to broadly elliptic, obtuse at the base, obtuse and apiculate at the apex, revolute, glabrous abaxially and adaxially and densely reticulate, 10–11 lateral veins per side. Flowers solitary, fragrant, white, 5.5–6.5 cm diam, flower bud 3.1–2.0 cm, broadly ellipsoid, obtuse at the base, apiculate at the apex, spathaceous bracts 2, mostly glabrous, the margin and outer apex shiny brownish pubescent, peduncular internodes 0.1–0.5 × 0.4–0.6 cm, shiny brownish pubescent, sepals 3, greenish white, 3.3–3.4 × 0.9–1.1 cm, oblong, slightly obovate, glabrous, outer petals creamy white, 3.1–3.2 × 1.5– 1.6 cm, narrowly obovate, wider in upper third, inner petals 2.3–2.4 × 0.9–1.1 cm, narrowly obovate, wider in upper third, creamy white, stamens 38–42 (determined from scars), gynoecium sessile, ellipsoid, greenish, carpels 20–22, blackish after drying, glabrous, stigmas 2 mm long, turning rusty brownish, recurved. Fruit 4.4–4.5 × 2.4–2.5 cm, oblongoid, follicles 1.0–2.0 × 0.8–0.9 cm, apiculate, seeds 1–2 per follicle, 0.9–1.0 × 0.6–0.8 cm, prismatic-triangular, orange-red.

Distribution, habitat and phenology:— Endemic to Sierra del Merendón, Cortés Province, ( Honduras), in disturbed, mid-elevation broadleaf forest ( Fig. 1 ; Table 2 ) with low numbers of vines, lichens and epiphytes (ferns and bromeliads) in a disturbed habitat with medium-light competition. Flowering June (flower buds, too).

Etymology and ethnobotany:— In honour of local guide, Pastor Cortés, from Buenos Aires de Bañaderos, Cortés Province ( Honduras), who assisted on six field expeditions with the second author from 2004. He is outstanding in his knowledge of local plants, his ability as a plant spotter and collector and his skill, conscientiousness and kindness as a guide. No ethnobotanical information has been recorded for the species.

Notes:— Magnolia pastorcortesii belongs to M. sect. Magnolia and is the only species of Magnolia in Honduras with broadly obovate leaves ( Table 3 ).

Conservation status:— Critically endangered (CR), IUCN criterion B1ab(iii). Although found within Parque Nacional Cusuco, the known extent of occurrence (EOO) is less than 10 km 2 and its habitat is disturbed ( Table 1 ). Only two trees have been recorded (their precise location is not given for conservation purposes), both at the type locality. One tree had an unhealthy appearance: there were three cut-off stumps, and the only stem still standing had severe apex damage; new shoots were observed on stumps and low on the standing tree. There was heavy invertebrate damage to the leaves (leaf-mining, possibly by Agromyzidae fly larvae as indicated by the double frass line; leaf-eating by undetermined agents; and skeletonizing by micro-Lepidoptera); minor damage from woodboring, stem mining and petal eating were also observed. The taller tree was healthy with a straight and symmetrical trunk (forking at eight metres), with low invertebrate damage to the leaves. To our knowledge, M. pastorcortesii is not only extremely rare but also confined to a relatively accessible area. Considering this, we are not publicizing further details of its location.

Additional specimens examined:— HONDURAS. Depto. Cortés: Buenos Aires to Base Camp, west of Buenos Aires , Parque Nacional Cusuco , Sierra del Merendón , west of San Pedro Sula , 25 Jul 2011 (fl bud), Cortés 14153-I ( IBUG!, MO, TEFH) .

Figures

FIGURE 1. Geographic distribution of Honduran Magnoliaceae.

FIGURE 12. Magnolia pastorcortesii. A. Flowering branch. B and D. Fruits showing dorsal dehiscence. C Leaves. E. Gynoecium after falling of petals and sepals. Drawings by Esaú Vázquez-Verdejo.

FIGURE 13. Magnolia pastorcortesii. A. Flowering branch and fruit. B. Flower. Photographs by Jeanne Sampier.

FIGURE 14. Magnolia pastorcortesii. A–C. Tree in habitat, with a red band. D–E. Tree trunks showing bark texture. Photographs by Pierre-Louis Robertson, 2017.

FIGURE 15. Magnolia pastorcortesii. A and B. Leaf (upper side and underside, respectively). C. Flower at the female phase of protogyny, with sepals nearly perpendicular to petals. D. Flower decaying after male phase. E. Gynoecium after the fall of sepals and petals. F. Spathaceous bract covering the flower bud. G. Flower bud without spathaceous bract. H. Early, latent, leaf bud. I & J. Flowers after the male phase with heavy insect damage: petal sucking (dots) and eating, respectively. K. Leaf mining, not inhabited. L. Leaf eating. M. Skeletonizing of leaves by microlepidoptera. N. Stem mining. Photographs by Pierre-Louis Robertson, 2017.