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

Figs 5 , 6

Type.

Vietnam. Lâm Đ ồng Province: Đà Lạt, Bidoup Nui Ba National Park, 1,500-1,700 m elevation, at damp places under forest, 29 Nov 2019, Jin-hong Dai and Ying Liu 836 (holotype: PE; isotypes: A, SYS, VNMN) .

Diagnosis.

Resembles P. banaensis , P. elliptica and P. dispar in having hyaline hairs, raphide crystals, somewhat elliptic leaf blade and umbels with very short or no peduncles but differs markedly from P. banaensis in the indumentum of the stems and petioles (both pubescent with stellate hairs when young, petioles hispid with long bristles vs. densely villous with appressed hyaline uniseriate hairs), and from the latter two species in height (40-120 cm vs. up to 45 cm), habit (shrubby vs. herbal), anther color (pink vs. yellow) and the morphology of connectives (prolonged below anthers vs. not prolonged). Also resembles P. setotheca and P. ovalifolia in habit, leaf size and shape but differs in petiole hispid with stout, 2-4 mm long bristles (vs. glabrous in P. setotheca and densely hirsute with soft hairs in P. ovalifolia ) and umbels with 0-2 mm peduncles (vs. peduncles 8-18 mm long in P. setotheca and 10-30 mm long in P. ovalifolia ).

Description.

Shrubs, 40-120 cm tall, branched, with raphides in all parts. Stems obtusely 4-sided when young, pubescent with brownish-yellow stellate hairs and rarely uniseriate hyaline hairs (both composed of elongated cells) when young, glabrescent when mature. Leaves opposite, equal or subequal in a pair; petiole 1.2-6 cm long, pubescent with brownish-yellow stellate hairs when young, hispid with stout, 2-4 mm long bristles; leaf blade broadly elliptic to elliptic, 5.6-15 × 1.9-6.4 cm, papery to stiffly papery, pubescent with brownish-yellow stellate hairs when young, glabrous on the upper surface and sparsely pubescent along veins on lower surface when mature, often 5-veined with the marginal two slightly inconspicuous and the inner two diverged from the midvein above the base, base cuneate, margin entire, apex acuminate, short acuminate, rarely acute. Inflorescences terminal and axillary, umbellate, 2-11-flowered, subtended by two sessile bracts; sessile or with peduncle up to 2 mm long. Flowers 4-merous; pedicel 8-13 mm long (16-25 mm in fruit), glabrous; hypanthium funnel-shaped, 5-7 mm long, pubescent with multiseriate hairs and sparsely so with stellate hairs; calyx lobes triangular-ovate, 6 mm long, glabrescent; petals pinkish-white, broadly ovate, oblique, ca. 10 mm long, apex acute; stamens isomorphic, filaments ca. 6 mm, anthers pink, lanceolate, ca. 6 mm, connective decurrent, prolonged below anther, forming a spur dorsally; ovary half as long as hypanthium (crown excluded), ovary crown wedge-like, 4-lobed; style 15 mm long. Capsule cup-shaped, ca. 7 × 6 mm, 4-sided; hypanthium 8-ribbed; crown enlarged enclosing an obpyramidal space; placental column unbeaked, 4-horned; placenta thready.

Phenology.

Flowers and old fruits in November.

Etymology.

The specific epithet is based on the stout long bristles on the petiole of this species.

Distribution.

Perilimnastes setipetiola is currently known from Đà Lạt, Lâm Đ ồng Province, Vietnam (Fig. 1 ). It occurs at damp places in forests, at 1,500-1,700 m elevation.

Additional specimen examined.

Vietnam. Lâm Đ ồng Province: Lạc Dương district, 40 km to northeast from Đà Lạt city. Closed primary wet broadleaved cloud forest on southwest macroslope of Hon Giao mountain ridge at 1,600-1,700 m elevation, 21 Apr 1997, L.Averyanov, N.Q.Binh, N.T.Hiep, VH 4133 [P (P05200269)].

Figures

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

Figure 5. Holotype of Perilimnastes setipetiola, Jin-hong Dai and Ying Liu 836 (PE). The inset shows raphides (as white oblong spots) on adaxial leaf surface under stereoscope. Scale bars: 5 cm, 1 mm (inset).

Figure 6. Perilimnastes setipetiola A habit B adaxial (top) and abaxial (bottom) leaf surfaces C a flowering branch D a branch showing hispid petioles and terminal and axillary infructescences E top view of a flower F longitudinal section of a flower showing the isomorphic stamens G longitudinal section of an old capsule showing enlarged ovary crown and morphology of the placental column and placentas. Scale bars: 5 mm (E, F); 3 mm (G). All from Jin-hong Dai and Ying Liu 836 (A, PE, SYS).