Perilimnastes multisepala J.H.Dai, T.V.Do & Ying Liu, 2023

Dai, Jin-Hong, Van Do, Truong & Liu, Ying, 2023, Four new species of Perilimnastes (Sonerileae, Melastomataceae) from Vietnam, PhytoKeys 235, pp. 1-19 : 1

Perilimnastes multisepala J.H.Dai, T.V.Do & Ying Liu sp. nov.

Figs 2 , 3 , 4

Type.

Vietnam. Qu ảng Nam Province: Đ ại Lộc, about 400 m south of Khu Du Lich Sinh Thai Khe Lim, along newly opened road, 574 m elevation, on rocks along a stream, 23 Nov 2019, Jin-hong Dai and Ying Liu 821 (holotype: PE; isotypes: A, SYS, VNMN) .

Diagnosis.

Resembles P. fruticosa and P. stenophylla in the habitat preference, habit, leaf and inflorescence morphology but differs from these species in the petals 28 × 9 mm, apex long acuminate (vs. 8.5-16 × 3.5-5 mm, acuminate, and 12 × 6 mm, short acuminate), calyx lobes 4-8 (vs. 4) and pedicels only 1-2 mm at fruiting stage (vs. 10-15 mm).

Description.

Shrubs, much-branched, up to 0.8 m tall, with druses in many parts. Stems obtusely 4-sided, slightly compressed when young; branchlets glabrous, sulcate, nodes only pubescent with uniseriate hairs when young. Leaves opposite, equal to distinctly unequal in a pair, pubescent with brownish-yellow stellate hairs only when young, glabrous when mature; petiole 0-10 mm; leaf blade obovate-lanceolate, oblong-lanceolate to oblanceolate, 2.4-8 × 0.7-2.4 cm, subcoriaceous, 3-veined with the lateral two veins often diverged from the midvein above the base, dark green adaxially, pale green abaxially, base cuneate, margin entire, apex obtuse, acute, rarely shortly acuminate. Inflorescences terminal, cymose contracted to umbellate, solitary or 2-flowered, rarely 3-flowered; peduncle ca. 1 mm long, sometimes sessile, subtended by a pair of bracts to 5 mm long. Flowers 4-merous; pedicel 1-2 mm long, glabrous; hypanthium funnel-shaped, 7-8 mm long, sparsely pubescent with stellate hairs; calyx lobes linear, laterally compressed, alternipetalous 4, 8-10 mm long, antepetalous 0-4, 3-8 mm long, sparsely pubescent with stellate hairs; petals pinkish purple, 28 × 9 mm, ovate, slightly oblique, apex long acuminate, abaxially very sparsely pubescent with stellate hairs; stamens 8, isomorphic, filaments 7-9 mm long, glabrous, anthers lanceolate, yellow, 9 mm long, connective decurrent, tuberculate ventrally, forming a spur dorsally; ovary half as long as hypanthium (crown excluded), ovary crown wedge-like, 4-lobed; style 22 mm long. Capsule cup-shaped, 7-8 × 7 mm, 4-sided; hypanthium 8-ribbed; crown enlarged enclosing an obpyramidal space; placental column unbeaked, 4-horned; placenta thready.

Phenology.

Flowers, young fruits and old fruits in November.

Etymology.

The specific epithet is based on the 4-8 calyx lobes of this species.

Distribution.

Perilimnastes multisepala is currently known from Đ ại Lộc, Quảng Nam Province, Vietnam (Fig. 1 ). It grows on rocks along streams in the forest, at 574 m elevation.

Figures

Figure 1. Distribution of Perilimnastes multisepala (triangle), P. setipetiola (square), and P. uniflora and P. banaensis (solid circle).

Figure 2. Holotype of Perilimnastes multisepala, Jin-hong Dai and Ying Liu 821 (PE). The inset shows druses (as white spots) on adaxial leaf surface under stereoscope. Scale bars: 5 cm, 1 mm (inset).

Figure 3. Perilimnastes multisepala A habit B adaxial (top) and abaxial (bottom) leaf surfaces C close-up of a branchlet showing a 2 - flowered cyme. All from Jin-hong Dai and Ying Liu 821 (A, PE, SYS).

Figure 4. Perilimnastes multisepala A top view of a flower B longitudinal section of a flower showing the isomorphic stamens C top view of a young capsule D lateral view of a young capsule E top view of an old capsule F longitudinal section of an old capsule showing enlarged ovary crown and morphology of the placental column and placentas. Scale bars: 5 mm (B); 3 mm (F). All from Jin-hong Dai and Ying Liu 821 (A, PE, SYS).