Scientific name: Homalium glandulosum Tagane & V. H. Nguyen
English name:
Vietnamese name: Chàn ra quả đầu
Other name:

Small tree, 9 m tall, DBH 15.6 cm; bark gray-brown; branchlets very sparsely pubescent, soon glabrous, with many lenticels, which are narrow to broadly elliptic, 0.3–0.9 × 0.1–0.25 mm, whitish; young twigs blackish when dry, old twigs grey-brown. Leaves: simple, alternate, petiole 2.5–5 mm long, sparsely pubescent when young, blackish when dry; leaf blade ovate to elliptic-ovate or oblong-ovate, (2.4–)3.5–9.8 × (1.0–)1.2–3.1 cm, papery, very sparsely pubescent on both surfaces, apex acuminate to acute, rarely obtuse, with a gland on tip, base cuneate, with 2–5 pairs of stalked glands at border with petiole, margin crenulate with glandular teeth; midribs prominent on both surfaces, glabrescent, secondary veins 6–7 pairs, arising at an angle of 40–45 degrees from the midrib, slightly prominent on both surfaces, tertiary veins reticulated, visible when dry. Stipules narrowly triangular, ca. 5 × 1 mm, thinly papery, with 4–6 glandular teeth per side, glands often stalked, apex acute, with a gland on tip, blackish when dry, very sparsely pubescent, caducous. Inflorescences axillary, pendant, racemes or racemiform panicles with flowers borne singly on rachis or in clusters of up to 3 sometimes on short branches, 4–9 cm long, 7–20 flowered; rachis densely pubescent with spreading hairs except glabrous and lenticellate basally; bracts caducous, not seen. Pedicels 2.5–3.5 mm long, densely pubescent with spreading hairs; bracteoles narrowly ovate, 2.5–3 mm long, margin with 3–5 stalked glands per side, glabrous except near base, caducous. Flowers fragrant, 6–8 mm in diam.; calyx tube ca. 2.5 mm long, densely pubescent with spreading hairs; sepals 8, narrowly oblanceolate, ca. 3 × 0.5 mm long, membranous, with conspicuous midvein, light green in vivo, glabrescent except near basal part on both surfaces and ciliate margin, hairs spreading, 0.6 mm long, apex apiculate, with a gland on tip; petals 8, oblanceolate, 3.5 × 1.1 mm, membranous, with conspicuous midvein and lateral veins, whitish in vivo, glabrescent except lower 1/3 on both surfaces, margin ciliate with spreading hairs, hairs ca. 0.6 mm long, apex obtuse to acute. Disk glands 8, ca. 0.3 mm in diam., orange in vivo, black when dry, stipitate, stalk ca. 0.15 mm long, sparsely hairy. Stamens 8, filaments ca. 5.5 mm long, sparsely spreading hairy in lower 3/5; anthers ca. 0.4 mm long, longitudinally and extrorsely dehiscent. Ovary semi-inferior. Styles 3 or 4, filiform, ca. 5 mm long, united in lower 1/3, hairy in lower 1/2, hairs spreading; placentas 3 or 4, each with (3–)4 ovules, sparsely hairy inside. Fruits not seen.

Distribution

So far known only from the type locality.

Habitat and Ecology

Rare in hill evergreen forest, at alt. 453 m. Flowering specimens were collected in July.

Etymology

The specific epithet ‘glandulosum’ reflects the existence of distinct glands, often stalked, on stipule, leaf base and bracts.

Conservation status

Data Deficient. Only one flowering individual was found in a protected area of Vu Quang National Park. Further efforts for finding additional individuals/populations are needed to evaluate its conservation status.

Note

In Vu Quang National Park, another species of Homalium, H. cochinchinense, occurs in lowland forest (e.g., alt. 70 m, 27 July 2015, Tagane et al. V3818 (BKF!, DLU!, FU!, NTU!, the herbarium of Vu Quang National Park!). The species is easily distinguished as in the above diagnosis and the following key.