Magnolia unicarmensis A.F.Montoya

Montoya-López, Andres Felipe & Bota-Sierra, Cornelio Andrés, 2023, Magnolia unicarmensis (Magnolia subsect. Dugandiodendron; Magnoliaceae): a new species from tropical montane forests of Antioquia, Colombia, Phytotaxa 626 (1), pp. 41-50 : 42-49

Magnolia unicarmensis A.F.Montoya –López & C.Bota–Sierra, sp. nov. ( Figs 1–5 )

Type:— COLOMBIA. Antioquia: La Unión - El Carmen de Viboral, between veredas San Juan ( La Unión ) and La Honda ( Carmen de Viboral ) 5°56’15.64”N, 75°17’4.09”W, 2640 m.a.s.l., 14 Sep 2023 (flower, bud and fruit), Montoya, Bota & Orozco s.n. (holotype: HUA 232719 and 232720) .

Magnolia unicarmensis is most similar to M. coronata but differs in having smaller leaf blades, 3.2–6.7 × 1.9–3.9 cm vs. 6.5–16.5 × 4.0–8.0 cm, leaf shape obovate, base cuneate and midrib extending to a small prolongation in the emarginate apex vs elliptic–obovate leaf without apical prolongation, woolly pubescence on the abaxial side of leaves only in midrib vs long yellowish or brown hairs covering the leaf, prefoliation marks on the lamina absent vs conspicuous prefoliation marks on the lamina, pubescence on the stipules golden woolly vs glabrous stipules and fruit glabrous vs pubescent ( Table 1 ).

Trees 6–15 m tall, diameter at breast height up to 31.8 cm; bark grey; twig internodes glabrous with a few lenticels, 0.63–0.93 cm long, 0.22–0.46 cm in diameter. Leaves with petioles 0.4–0.8 × 0.1–0.2 cm, sometimes with golden hairs, blades obovate, base cuneate with small pubescent midvein prolongation in the emarginate apex, 3.2–6.7 × 1.9–3.9 cm, margin entire, adaxially glabrous without prefoliation marks on the lamina, abaxially woolly, densely yellowish pubescent only along the midvein. Lateral veins 11–17 on each side of midvein, inconspicuous adaxially, midvein impressed above, prominent beneath, stipules 1.2–4.4 cm × 0.3–0.5 cm, golden woolly pubescent. Flowers 5.1–6.4 cm in diameter, terminal, solitary, fragrant, peduncle 0.6–0.8 cm long, bud ellipsoid, 1.4–2.1 × 1.0– 1.6 cm, hypsophylls 1, abaxially golden woolly in a line, sepals 3, reddish with yellow, oblong, glabrous, base flat, apex rounded, 2.4–2.8 × 1.3–1.9 cm, petals 6–8, adaxially white, cream and salmon, abaxially white with fuchsia, spatulate–obovate gradually narrower towards the base, the three outer ones 2.4–3.4 × 1.4–1.9 cm, inner petals three to five 2.2–3.5 × 0.7–1.6 cm, stamens 92–100, 0.75–0.86 cm long, the connective 0.29–0.46 cm long, brittle and entangled, gynoecium, 0.96–1.05 × 0.7–0.74 cm, elliptic mustard yellow, glabrous, stigma 0.2–0.4 cm long, yellow. Mature fruits ellipsoid glabrous, lemon green with black spots on the ridges of carpels, 3.0–3.6 × 2.0– 2.4 cm, with 6–7 carpels, seeds 1–2 per carpel, sub–prismatic, angled, 1.0–1.3 × 0.8– 0.8 cm.

Distribution, habitat and ecology:— Endemic to tropical mountain forest on the central Cordillera, between San Juan (La Unión) and La Honda (Carmen de Viboral). Buds, flowers and fruits observed August and September (2023). No seedlings observed.

Etymology:— Referring to its distribution between La Union and El Carmen de Viboral.

Conservation status:— Proposed as critically endangered under criteria B1 ab(i,ii,iii,v) of IUCN (2012) because the extent of occurrence estimated to be less than 100 km 2.

Figures

FIGURE 1. Distribution of Magnolia subsection Dugandiodendron in Antioquia, Colombia.

FIGURE 2. Habitat of Magnolia unicarmensis in Antioquia, Colombia. A and B view to vereda La Honda (Carmen de Viboral). B. M. unicarmensis with flower. Photos by A.F. Montoya-López.

FIGURE 3. Magnolia unicarmensis. A and B. Flower bud and stipules. C. Flower in early female phase. D, E and F. Flower after male phase, stamens falling. Photos by A.F. Montoya-López.

FIGURE 4. Magnolia unicarmensis. A. Leaf. B. Twig. C. Leaves and stipules in the treetop. D and E. Fruit. Photos by A.F. Montoya- López.

FIGURE 5. Comparison of leaves in four species of Magnolia subsection Dugandiodendron from Antioquia, Colombia. A. Adaxial B. Abaxial. The outer bigger leaf is from M. yarumalensis (cultivated in La Ceja, Antioquia). Inner leaves: bigger top right M. guatapensis (from type locality), medium size to the left M. coronata (from type locality), and smaller to the left down M. unicarmensis (from type locality). Notice the size differences between species, the presence of prefoliation marks on the lamina of M. guatapensis and M. coronata, as well as the difference in abaxial coloration and pubescence type. Photos by A.F. Montoya-López.