Garcinia exigua Nazre

Ngernsaengsaruay, Chatchai, Chanton, Pichet, Leksungnoen, Nisa, Chaiprasongsuk, Minta & Thunthawanich, Raweewan, 2024, A taxonomic revision of Garcinia section Garcinia (Clusiaceae) in Thailand, PhytoKeys 244, pp. 175-211 : 175-211

2. Garcinia exigua Nazre , Phytotaxa 373 (1): 28. figs 2 g, 3 i & 10. 2018.; Ngerns. et al., Thai Forest Bull., Bot. 51 (1): 36–44. figs 1–3. 2023.

Fig. 4

Type.

Malaysia, Borneo, Sarawak, Bintulu, Buan Forest Reserve, 18 Sep 1972, P. Chai S 31750 (holotype SAR, reported by Nazre et al. 2018, not seen; isotype L [L 2403372, photo seen]).

Description.

Habit trees, 2.5–20 m tall, 20–100 cm GBH, sometimes with buttresses near the base of the main stem of large trees; latex yellow, sticky; branchlets green, 4 - angular, glabrous. Bark brown or dark brown, after the peel pale yellow or pale brown, mottled, flaking and leaving roundish or irregularly shaped scars; inner bark red. Leaves: lamina narrowly elliptic, elliptic, broadly elliptic, sometimes obovate, 3–6.3 × 1–3.2 cm, apex narrowly obtuse or obtuse, base cuneate, margin entire and finely revolute, coriaceous, smooth, shiny dark green above, paler below, glabrous on both surfaces, midrib raised on both surfaces, secondary veins 10–18 each side, curving towards the margin and connected in distinct loops and united into an intramarginal vein, faint above, inconspicuous below, with intersecondary veins, veinlets reticulate, faint on both surfaces, with a few scattered black gland dots on both surfaces, interrupted long wavy lines of differing lengths, nearly parallel to the midrib, running across the secondary veins to the apex or the margin, visible on both surfaces especially on the lower surface of dry leaves; petiole green, 0.3–1 cm long, 1–1.5 mm in diam., grooved above, finely transversely rugose, glabrous, with a basal appendage clasping the branchlet; young leaves pale green, glossy; fresh leaves brittle when crushed; dry leaves pale brown or reddish brown. Inflorescences terminal, in fascicles of 3 male flowers and usually solitary in female flowers (observations based on infructescence); bracts 2, caducous, green or brownish green, conduplicate with a central keel, ovate, 8–10 × 4–5.5 mm, apex acuminate, thinly coriaceous (of male inflorescences). Flowers: sepals and petals glabrous. Male flower buds subglobose to globose, 3.5–5.5 mm in diam. Male flowers lightly fragrant, 1.5–2 cm in diam., the middle flowers always largest; bracteoles caducous; pedicel pale green, turning pale yellow, 3–4.5 mm long, 1.3–1.7 mm in diam., glabrous; sepals 4, pale yellow, concave, thinly coriaceous, with wavy lines outside, the outer pair broadly ovate, 4.2–5 × 3.5–5 mm, apex acute, the inner pair elliptic or broadly elliptic, 4.2–6 × 3–4.5 mm, apex obtuse; petals 4, pale yellow, elliptic, 6.5–9 × 3.5–8 mm, subequal, apex obtuse, margin revolute, thinly coriaceous, with wavy lines outside; stamens numerous, united into a single 4 - lobed bundle, surrounding a pistillode, lobes 3–3.5 × 3–4 mm; filaments 0.5–0.7 mm; anthers 0.9–1.2 × 0.8–1 mm; pistillode fungiform, 3–3.5 mm long; sterile stigma yellow, sessile, convex, weakly 4 - lobed, 2.5–3 mm in diam., smooth. Female flowers not seen. Fruits green, smooth with fine longitudinal striate, glabrous, with a sticky yellow latex, subglobose, globose or broadly ellipsoid, 1–1.3 × 0.8–1.1 cm, pericarp coriaceous; persistent stigma dark brown or blackish brown, flattened or slightly convex, 2–3 mm in diam., weakly 4 - lobed; persistent sepals green, concave, coriaceous, lanceolate-ovate or ovate, 3.5–5.5 × 3–5 mm, the outer pair slightly smaller than the inner pair, apex acute; fruiting stalk green, 1–2 mm long, 1–1.8 mm in diam., glabrous. Seeds 1, brown (dark brown when dry) mottled with irregular lines, ellipsoid, c. 6 × c. 3.5 mm, c. 1.8 mm thick, compressed, rounded at both ends, with a thin fleshy pulp. The morphological characters and data reported here for this species were mostly taken from Ngernsaengsaruay et al. (2023 a).

Distribution.

Thailand, Malaysia [Borneo, Sarawak (Bintulu, Buan Forest Reserve; Mulu National Park: Matong Ubong, Ulu Matong, Sungai Ubong)]; Brunei [Temburong (Ulu Belalong)].

Distribution in Thailand.

Peninsular: Krabi.

Habitat and ecology.

It is found in dry evergreen forest on limestone hills and littoral dry evergreen forest on limestone hills, 50–100 m amsl.

Phenology.

Flowering January to March; fruiting April to June.

Conservation status.

Garcinia exigua is a rare species in Borneo, and is represented only from three localities in lowland and hill forest in Sarawak and Brunei ( Nazre et al. 2018). In Thailand, the species is known only from two localities in Krabi Province, but to be expected in other limestone hills. Globally, it is known only from Borneo to Thailand, and has an Extent of Occurrence (EOO of 51,767.17 km 2) and a relatively small Area of Occupancy (AOO of 16 km 2) which lies within protected and non-protected areas. It is inferred to be experiencing a continuing decline in habitat area, extent, and quality. We therefore consider the conservation assessment as Vulnerable [VU B 2 ab (iii)].

Etymology.

The specific epithet of Garcinia exigua is a Latin word, referring to the small size of all parts in the specimens ( Nazre et al. 2018).

Vernacular names.

Phawa bai lek krabi (พะวาใบเล ็ กกระบ ี ่) ( Ngernsaengsaruay et al. 2023 a); Kandis ( Sarawak) from the material Runi S. Pungga & P. C. Yii S 61132 (K, L [L 3811193], as Garcinia sarawhensis Pierre ).

Uses.

Not known.

Notes.

Garcinia exigua is recognized by the following characters: (1) The leaves and fruits are small. (2) The fresh leaves are brittle when crushed. (3) The stamens of the male flowers are united into a single 4 - lobed bundle, surrounding a pistillode, and (4) The bark is mottled, flaking and leaving roundish or irregularly shaped scars similar to the bark of some species of Lagerstroemia L. in the Lythraceae , e. g., L. duperreana Pierre ex Gagnep. , L. floribunda Jack and some species of Terminalia L. in the Combretaceae , e. g., T. corticosa Pierre ex Laness.

According to Nazre et al. (2018), the shape and size of leaves of Garcinia exigua are elliptic and 0.8–2.1 × 0.3–1 cm; however, from our observations, we found the leaves can be narrowly elliptic to broadly elliptic, sometimes obovate, and larger, 3–6.3 × 1–3.2 cm.

As mentioned by Nazre et al. (2018), the shape, size, and color of fruits of Garcinia exigua are globose or ellipsoid, 9.5–10.5 × 8.5–11 mm, and shiny green turning yellow when ripe; however, in this study, we found the fruits can be subglobose, globose or broadly ellipsoid, sometimes slightly longer, 1–1.3 × 0.8–1.1 cm, and green. However, we did not observe ripe fruits.

Additional specimens examined.

Thailand. Peninsular: Krabi [Wat Tham Suea (originally “ Tham Sue ” on the label), Mueang Krabi District, fr., 8 May 2002 (as Garcinia sp. ), P. Pooma et al. 3612 ( BKF, QBG); Ko Hong, trail up to view point, Than Bok Khorani National Park, Mueang Krabi District, male fl., 13 Feb 2022, C. Ngernsaengsaruay et al. G 27-13022022 ( BKF, K, QBG); ibid., male fl., 13 Feb 2022, C. Ngernsaengsaruay et al. G 28-13022022 ( BKF, K, QBG)].

Malaysia. Borneo: Sarawak [Mulu National Park, Sg. Matong Ubong, fr., 11 Nov 1990, P. C. Yii & Runi S. Pungga S 57293 (L [L 3810871], SAR [reported by Nazre et al. 2018], as Garcinia sarawhensis ); Mulu National Park, Ulu Matong, fr., 13 Nov 1990, P. C. Yii & Runi S. Pungga S 60529 ( BKF, L [L 3811190], as G. sarawhensis ); Mulu National Park, Sungai Ubong, fr., 19 Nov 1990, Runi S. Pungga & P. C. Yii S 61132 (K, L [L 3811193], SAR [reported by Nazre et al. 2018], as G. sarawhensis ). Brunei. Temburong [Ulu Belalong, 22 Jan 1994, Coode et al. 7886 (A [reported by Nazre et al. 2018]).

Figures

Figure 4. Garcinia exigua A habitat and canopy (top view) B stem, bark, and slashed bark with yellow latex C branchlets and leaves D branchlets and male inflorescences with male flower buds E, F branchlets, leaves, and young fruits. Photos: Chatchai Ngernsaengsaruay (A – D), Naiyana Tetsana (E, F).