Magnolia oscarrodrigoi A.Vázquez, Tribouillier & Archila, 2021

Vázquez-García, J. Antonio, Tribouillier-Navas, Erick, Archila, Fredy, Véliz, Mario, Peña, A. Salome Ortega & Shalisko, Viacheslav, 2021, Three new species of Magnolia (Magnoliaceae) endemic to the north-wet-arc in the Maya Highlands of Guatemala, Phytotaxa 529 (1), pp. 57-70 : 62

Magnolia oscarrodrigoi A.Vázquez, Tribouillier & Archila , sp. nov. ( Fig. 3 )

Type:— GUATEMALA. Alta Verapaz: municipality of Cobán, 1300 m, 15°28’46.2”N, 90°20’45.2”W, with Vochysia guatemalensis , Liquidambar styraciflua , Toxicodendron striatum , Pinus maximinoi , Syzygium jambos , Persea schiedeana , on the banks of the Cahabón River; Jun 2010 (fl, fr), Tribouillier & Archila MG-106 (holotype: BIGU; isotypes: BIGU, IBUG).

Magnolia oscarrodrigoi belongs to M. sect. Magnolia and is similar to M. montebelloensis , differing from the latter in having elliptical leaves, longer peduncles, fewer spathaceous bracts, larger flowers, sepals and petals, smaller staminophore, more stamens and globose, glabrous polyfollicles ( Table 2 ).

Trees 20.0–25.0 m high, 100.0–120.0 cm DBH; petiole 2.0–3.0 cm long, pubescent on inner edges; leaves 9.0– 12.0 × 4.0–6.0 cm, elliptical, sharp-retuse apex, acute base, adaxially glabrous, abaxially strongly glaucous, sparsely pubescent but densely pubescent on the edges of new leaves, with 15–17 veins per side; flowers 14.0–16.0 cm in diameter, white; spathaceous bract 1, 4.5–5.0 × 3.8–4.2 cm, adaxially glabrous, abaxially golden yellow, hairy; flower stalk 2.5–3.2 × 0.7–0.8 cm, golden-yellow to hairy-orange-yellow, then glabrescent; sepals 3, 6.7–7.5 × 2.9–3.4 cm, narrowly obovate to elliptical, apex uncinate; petals 6, white, apically uncinate, the outer ones 7.0–7.8 × 2.5–3.1 cm, elliptical-obovate, the internal ones 5.5–6.0 × 2.2–3.0 cm, elliptical; staminophore 0.4–0.5 × 0.5–0.6 cm; stamens 107– 112, 1.3–1.5 × 0.3– 0.3 cm; gynoecium 2.4–2.7 × 1.2–1.7 cm, ovoid, glabrous, slightly glaucous green; polyfollicles 5.3–5.4 × 3.2–3.3 cm, globose glabrous, green, glaucous, follicles 32–39, 1.8–2.2 × 0.8–1.0 cm, apex straight, 0.3–0.5 cm long, persistent.

Distribution, phenology and ecology:— Known only from the type locality in gallery forest, from a small forest fragmented by urban expansion, 1300 m, flowering March–June, fruiting June–September.

Etymology:— Named for Oscar Rodrigo Archila Cortez, co-collector of the species.

Conservation status:— An endemic species with a localized distribution, currently known only from a single population in the border of Cobán and San Pedro Carchá municipalities, Alta Verapaz. Unofficially considered critically endangered (CR), using criterion D of the IUCN (2019). The number of observed mature trees in the known population is four, so it is safe to estimate that population is less than 50 individuals given the small extent of the gallery forest of the Cahabón River towards Cobán and the rare occurrence of mature individuals in this habitat discovered during field exploration. Additionally, it was deduced that the population in the type locality currently may be experiencing several threats because nearby unprotected forests have been cut down for urban and/or agricultural expansion.

Other specimens examined: — GUATEMALA. Alta Verapaz: municipality of San Pedro Carchá, 1300 m, 15°28’46.22”N, 90°20’28.79”W, with Vochysia guatemalensis , Liquidambar styraciflua , Toxicodendron striatum , Pinus maximinoi , Syzygium jambos , Persea schiedeana , on the banks of the Cahabón River, Jun 2010 (fl, fr), Tribouillier & Archila MG-012 (BIGU); municipality of Cobán, 1300 m s.n.m. 15°28’46.2”N, 90°20’45.2”W, 5 May 2021, Aguilar MG-107, MG-108 (BIGU).

Figures

FIGURE 3. Magnolia oscarrodrigoi. A. Flower in male phase. B. Gynoecium. C. Flower bud, D. Flower at female phase. Photographs by F. Archila.

Tables

Table 2. Comparison of Magnolia oscarrodrigoi with M. montebelloensis and M. faustinomirandae.

	M. oscarrodrigoi	M. montebelloensis	M. faustinomirandae
Tree height (m)	20.0–25.0	12.0–16.0	5.0–23.0
Leaf size (cm)	9.0–12.0 × 4.0–6.0	(9.0–)15.3–20.2(–22.2) ×	(10.0–)12.0–25.0 × (5.0–)7.0–12.0
		(3.5–)6.6–8.5(–10.8)
Leaf shape	Elliptical	Oblong-lanceolate	Obovate to elliptic (-lanceolate)
Lateral veins per side	15–17	11–12	10–14
Spathaceous bracts number	1	3	2
Flower size (cm)	14.0–16.0	11.0–11.8	9.0–15.0
Sepal size (cm)	6.7–7.5 × 2.9–3.4	4.2–4.3 × 2.7–2.8	4.1–6.0 × 2.6–3.1–3.3
Petal size (cm)	5.5–7.0 × 2.2–2.5	4.4–5.4 × 2.0–2.7	4.3–7.1 × 2.4–3.2
Peduncle length (cm)	2.5–3.2	1.0–1.5	1.5–3.4(–4.5)
Staminophore size (cm)	0.4–0.5 × 0.5–0.6	(0.7–)0.8–0.9 × 0.6–0.8	0.8–1.1 × 0.4–0.5
Stamen number	107–112	(53–)60–66(–85)	(97–)100–120
Fruit shape	Globoid	Oblongoid	Oblongoid
Fruit vestiture	Glabrous	Glabrescent to pubescent	Glabrescent to pubescent