Alphonsea phuwuaensis Leerat. & Chalermglin, 2020

Leeratiwong, Charan, Chalermglin, Piya & Johnson, David M., 2020, Two new species of Alphonsea (Annonaceae) from Thailand, Phytotaxa 429 (3), pp. 225-232 : 228-229

Alphonsea phuwuaensis Leerat. & Chalermglin , sp. nov. ( Figs. 1 , 3 , 5 )

Type:— THAILAND. Bueng Kan, Phu Wua Wildlife Sanctuary , 200 m elev., 3 May 2002, Pooma et al. 3418 (holotype: BKF!; isotype: L!) .

The species is distinct from most other Thai Alphonsea species by having the inside of the outer petals more densely hairy on the inner surface than on the outer.

Trees 4–15 m tall, bark brown, twigs lenticellate, glabrous or with sparse, brownish appressed hairs when young, later glabrous. Leaves with petioles 3–10 mm long, glabrous to sparsely hairy; blade elliptic, oblong, lanceolate-elliptic or oblong-lanceolate, 6.0–20.0 × 2.5–7.5 cm, apex acuminate or acute, the acumen 5–20 mm long, base cuneate, margins revolute, lamina shiny, glabrous on adaxial surface, glabrous except for occasional sparse hairs on midrib abaxially, primary vein sunken above, raised below, secondary veins 8–14 veins per side, tertiary veins reticulate, distinct on both surfaces. Inflorescences 1–3-flowered, extra-axillary or rarely leaf-opposed, peduncle 5–10 mm long, pedicels 7–15 mm long, brown pubescent, with an ovate bract near the base, 0.8–1.5 × 0.8–1.5 mm, pubescent outside and glabrous inside, buds conical. Sepals 3, brownish green, connate at base, ovate, 1.5–2.0 × 1.5–2.5 mm, apex obtuse, reflexed, sparsely pubescent outside, densely pubescent inside. Petals 6 in two whorls, outer petals creamy white to whitish yellow in vivo, brown in sicco, triangular-ovate, 6–10 × 4–6 mm, apex obtuse, pubescent on both sides, but inside denser than outside, inner petals creamy white to whitish yellow in vivo, brown in sicco, triangular-elliptic, 7.0–12.0 × 3.5–5.5 mm, apex acute to obtuse, pubescent outside, glabrous to pubescent at margin and apex inside. Stamens 25–30, ovate, elliptic or oblong-elliptic, 0.8–1.5 mm long, connective apex apiculate. Carpels 3–4 per flower, ovary oblong, 2–3 mm long, pubescent, stigma U-shaped, 0.2–0.3 mm long. Torus conical. Fruits consisting of 2–4 monocarps, greyish green in vivo when young, colour at maturity unknown, brown in sicco, ovoid, ellipsoid or cylindrical-ellipsoid, 0.8–2.0 × 0.7–1.0 cm, apex mucronate, smooth, sparsely covered with brown hairs or glabrous, with a longitudinal groove on abaxial side, constricted between seeds in dry monocarps, pedicel of fruit 2.5–3.0 cm long, stipes 1.5–3.0 mm long. Seeds unknown.

Distribution and Ecology:— Endemic to northeastern Thailand, in dry evergreen forest, 200–250 m elev.

Phenology:— Flowering February–August, fruiting May–August.

Local Name:— Tam yao phu wua (Thai).

Etymology:— The species name refers to the type locality of the species.

IUCN conservation status:— The species is only found in dry evergreen forest in Phu Wua Wildlife Sanctuary, Bueng Kan Province, and has a small population with only a few individuals. We assess it here as data deficient (DD) ( IUCN 2012) due to inadequacy of the distribution information; a further assessment is necessary when more data are available.

Additional specimens examined:— THAILAND. Bueng Kan: Phu Wua Wildlife Sanctuary , 250 m, 7 May 1997, Pooma 1581 ( BKF) ; Phu Wua Wildlife Sanctuary , 200 m, 27 August 2001, Pooma et al. 2818 ( BKF, L) ; Phu Wua Wildlife Sanctuary , 200 m, 3 May 2002, Pooma et al. 3410 ( BKF, L), Pooma et al. 3418 ( BKF, L) ; Phu Wua Wildlife Sanctuary , 2002, Pooma 3402 ( L) ; Phu Wua Wildlife Sanctuary , ca. 250 m, 15 June 2004, Wongprasert et al. 046-97 ( BKF) ; Phu Wua Wildlife Sanctuary , 220 m, 22 February 2019, Leeratiwong & Chalermglin 19-1422 ( BKF, PSU) .

Notes:— Alphonsea phuwuaensis can be distinguished from most other members of the genus in Thailand by having hairs on both surfaces of outer petals and a denser indument on the inner surface. It also has 3–4 carpels and smooth monocarps with mucronate apex. This species is only known at present from Phu Wua Wildlife Sanctuary, Bueng Kan Province, and further survey in nearby areas is needed to determine its distribution.

Figures

FIGURE 1. Distribution of Alphonsea longicarpa and A. phuwuaensis in Thailand.

FIGURE 3. Alphonsea phuwuaensis. A. Fruiting branch. B. Side view of flowers. C. Apical view of flowers. D. Young monocarps. E. Dry mature monocarps. (E. from Pooma 1581, BKF). Photos by C. Leeratiwong.

FIGURE 5. Alphonsea phuwuaensis. A. Fruiting branch. B. Flower, side view. C. Outer petal, abaxial view. D. Outer petal, adaxial view. E. Indumentum on abaxial surface of outer petal. F. Indumentum on adaxial surface of outer petal. G. Inner petal, adaxial view. H. Inner petal, abaxial view. I. Inner petal, side view. J. Stamen, abaxial view. K. Stamen, adaxial view. L. Carpel. M. Dry mature fruit (M. from Pooma et al. 3418, BKF). Drawn by W. Thammarong.