Research Article |
Corresponding author: Ying Liu ( liliumrosa@163.com ) Academic editor: Marcelo Reginato
© 2023 Jin-Hong Dai, Truong Van Do, Ying Liu.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Dai J-H, Van Do T, Liu Y (2023) Four new species of Perilimnastes (Sonerileae, Melastomataceae) from Vietnam. PhytoKeys 235: 1-19. https://doi.org/10.3897/phytokeys.235.112133
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Perilimnastes is a genus currently treated in the polyphyletic Phyllagathis. Recent phylogenomic analyses have identified a morphologically cohesive lineage referred to as the Phyllagathis (raphides) clade, which should be excluded from Phyllagathis and treated as a distinct genus under the name Perilimnastes. Morphological and phylogenomic data have confirmed that four new species collected from Vietnam are part of the Phyllagathis (raphides) clade. They are described herein as Perilimnastes multisepala, P. setipetiola, P. uniflora, and P. banaensis. Perilimnastes multisepala is phylogenetically closest to Phyllagathis setotheca, and morphologically to P. fruticosa and P. stenophylla, but is distinct in the 4- to 8-lobed calyx, 28 × 9 mm, apically long acuminate petals, and 1–2 mm pedicel at fruiting stage. Perilimnastes setipetiola, P. uniflora, and P. banaensis are phylogenetically most closely related. Perilimnastes uniflora is characterized by its prostrate habit, small size, glabrous, obovate to obovate-lanceolate leaf blade, and solitary flower. Perilimnastes setipetiola and P. banaensis resemble each other in habit, leaf size and shape, and sessile or near sessile inflorescences but can be easily distinguished by the indumentum of the stems and leaves.
Melastomataceae, Perilimnastes, Phyllagathis, taxonomy
Perilimnastes Ridl. was established based on P. fruticosa (Ridl.) Ridl. (
The classification of Asian Sonerileae at generic level has been a topic of ongoing controversy, particularly regarding the delimitation of Phyllagathis and various genera morphologically related to it (
During a field expedition in Vietnam, four species that were previously unrecorded in the Flora of Vietnam were collected from Đại Lộc, Quảng Nam Province (1 sp.), Đà Lạt, Lâm Đồng Province (1 sp.), and Hòa Ninh, Đà Nẵng (2 spp.) (Fig.
Morphological and distribution data were obtained through field, herbarium and literature surveys as well as observation of living plants in the facilities of Sun Yat-sen University. Specimens of the species concerned (GXMI, IBSC, IBK, KUN, PE, SYS) or their high-resolution photos (A, BM, C, E, G, K, NY, P, US) were examined. Species delimitation followed
According to previous phylogenomic analyses, P. multisepala is closest to Phyllagathis setotheca H.L.Li from China (
Perilimnastes setipetiola is resolved as sister to P. uniflora, and P. setipetiola-P. uniflora to P. banaensis (
Phylogenetic data and morphological comparison justify the recognition of P. multisepala, P. setipetiola, P. uniflora, and P. banaensis as distinct species in Perilimnastes. The formal taxonomic treatment of other species in the Phyllagathis (raphides) clade will be dealt with in another study.
The four new species are geographically quite isolated from related species previously discussed (Suppl. material
Vietnam. Quảng Nam Province: Đại 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).
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).
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.
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).
Flowers, young fruits and old fruits in November.
The specific epithet is based on the 4–8 calyx lobes of this species.
Perilimnastes multisepala is currently known from Đại Lộc, Quảng Nam Province, Vietnam (Fig.
Vietnam. Lâm Đồng 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).
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).
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).
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.
Flowers and old fruits in November.
The specific epithet is based on the stout long bristles on the petiole of this species.
Perilimnastes setipetiola is currently known from Đà Lạt, Lâm Đồng Province, Vietnam (Fig.
Vietnam. Lâm Đồng 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)].
Vietnam. Đà Nẵng: Hòa Ninh, Ba Na Hills, 1,360 m elevation, in forests on damp rocks along steam, 22 Nov 2019, Jin-hong Dai and Ying Liu 814 (holotype: PE; isotypes: A, SYS, VNMN).
Resembles P. guillauminii and P. rupicola in having raphide crystals, 3-veined leaves with cuneate base and somewhat acuminate apex, and narrow calyx lobes, but differs from P. rupicola in its pink anthers (vs. yellow) and from both in the stems glabrous except for minute brown glands when young (vs. covered with long bristles in P. guillauminii and hyaline uniseriate hairs in P. rupicola) and pedicel 4 mm long at fruiting stage (vs. 16 mm long in P. guillauminii and 22 mm long in P. rupicola).
Perilimnastes uniflora A habit B a flowering individual C close-up of a branchlet D adaxial (left) and abaxial (right) leaf surfaces E a flowering branch F close-up of an inflorescence showing a solitary flower G top view of a flower H longitudinal section of a flower showing the isomorphic stamens I longitudinal section of an old capsule showing enlarged ovary crown and morphology of the placental column and placentas. Scale bars: 5 mm (D, G, H); 2 mm (I). All from Jin-hong Dai and Ying Liu 814 (A, PE, SYS).
Shrublets or somewhat woody herbs, to 30 cm tall, with raphides in all parts. Stems prostrate at middle and lower parts, branched, with adventitious roots at lower nodes; branchlets quadrangular and with sparse minute brown glands when young, glabrescent; older branches obtusely 4-sided; leafy distally and leafless proximally. Leaves opposite, equal to unequal in a pair, with minute brown glands only when young, glabrescent when mature; petiole 0.5–2 cm long; leaf blade obovate to obovate-lanceolate, sometimes elliptic, 4.2–9.5 × 1.3–3.4 cm, papery, 3-veined with the lateral two veins diverged from the midvein at or above the base, green to dark green adaxially, pale green abaxially, base cuneate to narrowly cuneate, margin entire or inconspicuous minutely repand, apex acuminate to long acuminate, sometimes caudate. Inflorescences terminal, flower solitary, subtended by a pair of bracts ca. 4 mm long. Flowers 4-merous; pedicel ca. 2 mm long, 4 mm at fruiting stage, glabrous; hypanthium funnel-shaped, 5–6 mm long, glabrous except for minute glands; calyx lobes 4, linear, 6–9 mm long, with minute glands; petals pinkish-purple, 11–13 × 4–6 mm, ovate, minutely oblique, apex acute to short acuminate, glabrous on both sides; stamens 8, isomorphic, filaments pink, ca. 6 mm long, glabrous, anthers lanceolate, pink, 5–7 mm long, connective decurrent, forming two ventral lobes and a dorsal spur; ovary half as long as hypanthium (crown excluded), ovary crown wedge-like, 4-lobed; style 13–15 mm long. Capsule cup-shaped, ca. 5 × 5 mm, 4-sided; hypanthium 8-ribbed; crown enlarged enclosing an obpyramidal space; placental column unbeaked, 4-horned; placenta thready.
Flowers in June and produces old fruits in November.
The specific epithet is based on the solitary flowers of this species.
Perilimnastes uniflora is currently only known from Ba Na Hills, Hòa Ninh, Đà Nẵng, Vietnam (Fig.
Vietnam. Đà Nẵng: Hòa Ninh, Ba Na Hills, 1,360 m elevation, in forests on damp slopes near steam, 22 Nov 2019, Jin-hong Dai and Ying Liu 813 (holotype: PE; isotypes: A, SYS, VNMN).
Resembles P. ovalifolia and P. setipetiola in having raphide crystals, hyaline hairs, somewhat elliptic leaf blade, and umbels with very short or no peduncle, but differs in the stems and petioles densely villous with brown hyaline uniseriate hairs (vs. stems densely retrorse hirsute, glabrescent, and petioles densely hirsute to setose in the former species, and stems pubescent with brownish-yellow stellate hairs and rarely also hyaline hairs, petioles with brownish-yellow stellate hairs when young and hispid with long bristles in the latter).
Perilimnastes banaensis A habit B a branch with old capsules C close-up of a branchlet D adaxial (left) and abaxial (right) leaf surfaces E a sessile infructescence F longitudinal section of an old capsule showing enlarged ovary crown and morphology of the placental column and placentas. Scale bars: 2 mm (F). All from Jin-hong Dai and Ying Liu 813 (A, PE, SYS).
Shrubs to 60 cm tall, with raphides in all parts. Stems branched, prostrate at lower parts; branchlets obtusely 4-sided and densely villous with appressed, brown hyaline uniseriate hairs composed of much elongated cells and tipped with a brown glandular cell; older branches near terete and glabrescent; leafy distally and leafless proximally. Leaves opposite, equal to unequal in a pair; petiole 1.5–4.6 cm long, densely villous with appressed, brown hyaline hairs; leaf blade elliptic, 5.5–13 × 2.5–6.5 cm, thick papery, with minute brown glands when young on both surfaces, abaxially sparsely pubescent with appressed brown hyaline hairs, densely so along the veins, 3 or 5-veined, dark green adaxially, pale green abaxially, base acute to rounded, margin entire or sometimes inconspicuously minutely repand, apex short acuminate to acute. Inflorescences and flowers unknown. Infructescences terminal, umbellate, sessile, capsules 2–7, pedicel 5–13 mm long. Old capsules cup-shaped, ca. 5 × 5 mm, 4-sided; hypanthium 8-ribbed; crown enlarged enclosing an obpyramidal space; placental column unbeaked, 4-horned; placenta thready.
Old fruits in November.
The specific epithet is based on Ba Na hills, the type locality of this species.
Perilimnastes banaensis is currently only known from Ba Na Hills, Hòa Ninh, Đà Nẵng, Vietnam (Fig.
We are grateful to Dr. David E. Boufford and the anonymous reviewer for their valuable comments on the manuscript.
The authors have declared that no competing interests exist.
No ethical statement was reported.
This work was supported by the National Natural Science Foundation of China (grants 32170220), Natural Science Foundation of Guangdong Province (grant 2021A1515011214), and partly by the Ministry of Planning and Investment, Vietnam, and the Vietnam Academy of Science and Technology under the project code UQĐTCB.06/22–23 to TVD.
Methodology: YL. Writing: YL, JHD, TVD.
Jin-Hong Dai https://orcid.org/0000-0001-5069-6016
Truong Van Do https://orcid.org/0000-0002-0585-5513
All of the data that support the findings of this study are available in the main text or Supplementary Information.
Supplementary data
Data type: docx
Explanation note: table S1. Comparison of Perilimnastes multisepala and related species. The name of the new species is indicated in bold; table S2. Comparison of Perilimnastes banaensis, P. setipetiola, P. uniflora, and related species. The names of the new species are indicated in bold.