Garcinia santisukiana Ngerns. & Suddee

4. Garcinia santisukiana Ngerns. & Suddee View in CoL , Kew Bull. 77: 121. figs 1, 2. 2022.

Type.

Holotype, • Thailand, Ubon Ratchathani Province, Khong Chiam District, Na Pho Klang Subdistrict, Pha Taem National Park, Dong Na Tham Forest , in dry evergreen forest, 420 m alt., ♀ fl. & fr., 23 Sep 2020, C. Ngernsaengsaruay & W. Surawoot G 02-23092020, BKF!; isotypes: A!, K!.

Description.

Habit trees, 5–18 m tall, 20–85 cm GBH; exudate pale yellow, sticky; branchlets 4 - angular, glabrous. Bark greyish-brown to dark brown, scaly; inner bark pale yellow. Leaves elliptic or obovate, 2.7–9.7 × 1.5–4.3 cm, apex acute, sometimes retuse, base cuneate, margin entire, subcoriaceous or coriaceous, dark green above, paler below, glabrous on both surfaces, midrib flattened above, raised below, secondary veins 9–14 on each side, curving towards the margin and connected in distinct loops and united into an intramarginal vein, visible on both surfaces, with intersecondary veins, veinlets reticulate, faint on both surfaces, with scattered black gland dots on both surfaces, interrupted long wavy lines present, of differing lengths, nearly parallel to the midrib, running across the secondary veins to the margin, visible below; petiole 0.5–1.3 cm long, 1–1.7 mm diam., shallowly grooved above, glabrous, with a small basal appendage clasping the branchlet; fresh leaves brittle when crushed; young leaves red or reddish brown, turning pale green, glossy. Inflorescences on branchlets at leafless nodes, in fascicles of 3–5 flowered cymes or solitary. Flowers unisexual, lightly fragrant, 4–7 mm diam.; bracteoles 4, decussate, green; sepals and petals decussate, sepals green, glabrous, petals creamish white or pale yellow. Flower buds pale green, subglobose or globose, 2.5–3.5 mm diam. Male flowers mostly in fascicles of 3–5 flowers; bracteoles triangular, 0.3–0.7 × 0.6–1 mm, apex acute; pedicel green, 1–2 mm long, 1–1.7 mm diam., glabrous; sepals 4, semi-orbicular, c. 1 × 1–1.5 mm, apex rounded; petals 4, obovate, 3–5 × 2.2–3.2 mm, concave, apex rounded; stamens numerous, united into 4 bundles, each bundle 2–3 × 1.2–1.5 mm, creamish white; filaments very short; anthers small; pistillode mushroom-shaped, 3–3.6 mm long; sterile stigma pale yellow, sessile, convex, 1–1.5 mm diam., papillate. Female flowers solitary or in fascicles of 3–5 flowers; bracteoles semi-orbicular, 0.8–1 × 1–1.5 mm, apex rounded; pedicel green, 1.5–2.5 mm long, 1.5–1.8 mm diam., glabrous; sepals 4, equal, semi-orbicular, 1–1.5 × 1–2 mm, apex rounded; petals 4, suborbicular or obovate, 3–4 × 2.5–3.5 mm, concave, apex rounded; staminodes united into 4 bundles at the base of ovary, opposite petals; pistil mushroom-shaped; ovary green, subglobose, 1–2 × 1.8–2.2 mm; stigma pale yellow, sessile, convex, 2–2.2 mm diam., weakly or shallowly 4 - lobed, papillate. Fruits berries, subglobose or ovoid, 1.5–2.7 × 1–2.5 cm, green, turning red when ripe, smooth and glabrous, pericarp coriaceous, c. 0.8 mm thick, cut fruits with a sticky yellow exudate, with small persistent sepals; persistent stigma blackish brown, flattened, 2–2.2 mm diam., weakly or shallowly 4 - lobed, papillate; fruiting stalk 1.5–2.5 mm long. Seeds 1–2, brown mottled with pale brown, compressed, one side flat with conspicuous hilum, another side slightly convex, elliptic or oblong in outline, 1.5 – 2 × 1–1.5 cm, rounded at both ends, with a yellow fleshy pulp (Fig. 13 View Figure 13 ).

Distribution.

Known only from north-eastern and eastern regions of Thailand, but to be expected in Laos and Cambodia.

Distribution in Thailand.

North-Eastern: Buengkan, Nakhon Phanom; Eastern: Si Sa Ket, Ubon Ratchathani.

Habitat and ecology.

It is found in dry evergreen forests and deciduous dipterocarp forests on sandstone crevices, at elevations of 150–600 m a. m. s. l.

Phenology.

Flowering and fruiting more than once, flowering August to December, fruiting September to February and June.

Conservation status.

Garcinia santisukiana is known only from four provinces of Thailand, but to be expected in Laos and Cambodia. The species is known from small populations in the type and non-type localities, which lie within protected areas. It has an EOO of 29,848.67 km 2 and a small AOO of 20 km 2. Because of this species with narrow geographical range and the number of locations, we consider the conservation assessment here as VU [B 2 a, b (iii)].

Etymology.

The specific epithet of Garcinia santisukiana was in honour of the late Prof. Dr Thawatchai Santisuk (1944–2020), one of Thailand’s most widely respected plant taxonomists ( Ngernsaengsaruay and Suddee 2022).

Vernacular names.

Nuan santisuk (นวลส ั นต ิ ส ุ ข); Yang ueng (ยางอ ึ ่ ง) (Ubon Ratchathani, local people around Dong Na Tham Forest) ( Ngernsaengsaruay and Suddee 2022).

Uses.

The fleshy pulp surrounding the seeds is edible and has a sweet and sour taste.

Notes.

The morphological characters and data reported here for this species were mostly taken from Ngernsaengsaruay and Suddee (2022).

In addition to Ngernsaengsaruay and Suddee (2022), the natural distribution in Buengkan, Nakhon Phanom, and Si Sa Ket Provinces is newly recorded here.

According to Ngernsaengsaruay and Suddee (2022), the conservation status of Garcinia santisukiana was proposed as LC. In this study, because of this species with a narrow geographical range and a small number of locations, we therefore suggest the conservation status VU [B 2 a, b (iii)].

Additional specimens examined.

Thailand. North-Eastern: • Buengkan [ Chet Si Waterfall , Phuwua Wildlife Sanctuary, Ban Tong Subsistrict, Seka District, fr., 7 Jun 2008 (as Garcinia sp. ), T. Wongprasert 086-19 ( BKF)] ; • Nakhon Phanom [ Tat Kham Waterfall , Phu Langka National Park, Ban Phaeng District, fl., 25 Aug 2001 (as Garcinia sp. ), R. Pooma et al. 2646 ( BKF)] ; Eastern: • Si Sa Ket [ Khao Phanom Dong Rak (originally “ Dongrak Range at Chong Bat Lak ” on the label), Kantharalak District, ♂ fl., 16 Aug 1976 (as G. cf. merguensis and G. brevirostris , det. P. F. Stevens, Sep 1997), J. F. Maxwell 76-515 ( AAU, BKF) ; • Ubon Ratchathani [ Pha Chana Dai , Pha Taem National Park, fr., 28 Feb 2007 (as Garcinia sp. ), S. Suddee et al. 3075 (paratype BKF); • ibid., fl., 7 Nov 2018, S. Suddee et al. 5393 (paratype BKF) ; • ibid., ♂ fl., 10 Dec 2020, C. Ngernsaengsaruay & W. Surawoot G 05-10122020 (paratypes BKF, K) ; • Dong Na Tham Forest , Pha Taem National Park, Na Pho Klang Subdistrict, Khong Chiam District, ♀ fl. & fr., 23 Sep 2020, C. Ngernsaengsaruay & W. Surawoot G 03-23092020 (paratypes A, BKF, K) ; • ibid., fr., 23 Sep 2020, C. Ngernsaengsaruay & W. Surawoot G 04-23092020 (paratypes BKF)] .