ArticlePDF Available

Smilax bolavenensis, a new species of Smilacaceae from southern Laos


Abstract and Figures

A new species of Smilax, S. bolavenensis (Smilacaceae), is described from the Bolaven Plateau, southern Laos. It is similar to S. elegantissima in its elongated inflorescence with slightly zigzagged rachis longer than 20 cm, but the new species is distinguished by its terete stem and petiole (vs. 4-angled with each corner narrowly winged in S. elegantissima) and 42–54-flowered umbels (vs. 7–12). A description, photographs and preliminary conservation status are also provided for S. bolavenensis.
Content may be subject to copyright.
Phytotaxa 585 (1): 055–060
Copyright © 2023 Magnolia Press Article PHYTOTAXA
ISSN 1179-3155 (print edition)
ISSN 1179-3163 (online edition)
Accepted by Mark W. Chase: 3 Feb. 2023; published: 23 Feb. 2023
Licensed under Creative Commons Attribution-N.C. 4.0 International
Smilax bolavenensis, a new species of Smilacaceae from southern Laos
1Kagoshima University Museum, Kagoshima University, 1-21-30, Korimoto, Kagoshima 890-0065, Japan
2Faculty of Forest Science, National University of Laos, Dongdok Campus, Xaythany District, Vientiane Capital, Laos
3Department of Botany, Graduate School of Science, Kyoto University, Kitashirakawa-oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
*Corresponding author
A new species of Smilax, S. bolavenensis (Smilacaceae), is described from the Bolaven Plateau, southern Laos. It is similar
to S. elegantissima in its elongated inflorescence with slightly zigzagged rachis longer than 20 cm, but the new species
is distinguished by its terete stem and petiole (vs. 4-angled with each corner narrowly winged in S. elegantissima) and
42–54-flowered umbels (vs. 7–12). A description, photographs and preliminary conservation status are also provided for S.
Keywords: Bolaven Plateau, Liliales, Southeast Asian flora
Smilax Linnaeus (1753: 1028) became the sole genus of Smilacaceae after Heterosmilax Kunth (1850: 270) was
reduced to Smilax (Cameron & Fu 2006, Qi et al. 2013a, b). It consists of about 300 species, collectively distributed
in tropical, subtropical and temperate regions (Chen & Koyama 2000, POWO 2022). The species are dioecious, often
woody climbers and shrubs, sometimes herbs, with simple lamina with 3–7 main veins arising from the base, netted
leaf venation, axillary inflorescences are composed of 1(–3) umbel(s) or paniculately, racemosely or spicately disposed
several umbels, 6 tepals, superior ovary and drupes or berries (Chen & Koyama 2000, Qi et al. 2013a). In Laos, 19
species have been recorded (Gagnepain 1934, Koyama 1983, Newman et al. 2017 onwards, Kladwong et al. 2018,
The Bolaven Plateau, southern Laos, is one of the biodiversity hotspots in Indochina (Profile 2012). Indeed,
our recent extensive fieldwork carried out in the area 2018–2020 has resulted in discovery of more than 17 new
taxa endemic to the Bolaven Plateau and 70 new records for Laos (e.g., Souladeth et al. 2020, Tagane et al. 2020,
Phonepaseuth et al. 2021, Souvannakhoummane et al. 2021, Vongthavone et al. 2021, Yamazaki et al. 2021, Noyori
et al. 2022). During our botanical inventories, we collected seven species of Smilax, of which six were identified as S.
bockii Warburg ex Diels (1900: 252), S. corbularia Kunth (1850: 262), S. extensa Wallich in Hooker (1892: 309), S.
glabra Roxburgh (1832: 792), S. lanceifolia Roxburgh (1832: 792) and S. megacarpa Candolle (1878: 186). However,
one species did not match descriptions of species recorded in Laos and surrounding countries.
The two unknown specimens were collected during our field surveys in Bolaven Plateau in 2018 and 2019. We
examined the putative new species and referred to herbarium specimens at FOF and KAG and digital specimen images
available on online (e.g. JSTOR Global Plants Floral measurements were made on rehydrated
specimens, and we consulted the relevant literature (Gagnepain 1934a, Koyama 1975, 1983, Hô 2000, Li et al. 2011,
Heckroth et al. 2014, Sun et al. 2015, Jin et al. 2016, Qi et al. 2016, Newman et al. 2017 onwards, Baruah et al. 2018,
Kladwong et al. 2018, 2020, Feng et al. 2022). Based on these studies, it was clear this is an undescribed species,
which we formally described below.
56 Phytotaxa 585 (1) © 2023 Magnolia Press
Smilax bolavenensis Tagane & Soulad., sp. nov. (Figs 1, 2)
TYPE:LAOS. Champasak Province: Paksong District, near Nong Luang Village, Dong Hua Sao National Park (Bolaven Plateau),
15°04′44.53″N, 106°12′27.36″E, 1249 m a.s.l., 17 Dec 2019, Souladeth et al. L3342 (holotype: FOF 0006673; isotypes BKF, KAG
Smilax bolavenensis is similar to S. elegantissima Gagnepain (1934b: 619) from Vietnam in having an elongate inflorescence with slightly
zigzag rachis longer than 20 cm, but clearly distinguished from it by its terete stem and petiole (vs. 4-angled with each corner
narrowly winged) and 42–54-flowered umbels (vs. 7–12).
FIGURE 1. Smilax bolavenensis (holotype, Souladeth et al. L3342, FOF0006673).
A NEW SPECIES OF SMILAX BOLAVENENSIS Phytotaxa 585 (1) © 2023 Magnolia Press 57
FIGURE 2. Smilax bolavenensis. A. Leafy branch. B. Branch with staminate inflorescence. C. Abaxial leaf surface. D., E. Staminate
inflorescence. F. Longitudinal section of a staminate umbel. G. Bracteole. H. Staminate flower bud with bracteoles (left), staminate flower
bud (middle), and staminate flower bud outer three tepals and one inner tepal removed showing stamens (right). I. Outer tepals (top) and
inner tepals (bottom), adaxial side (left), abaxial side (middle and right). A–C from Tagane et al. L1964 (KAG); D–G from Souladeth et
al. L3342 (KAG). Scale bars: F = 5 mm, G–I= 2 mm. Photographed by S. Tagane.
Climbers to 4 m tall, all parts glabrous. Stems and branches subterete, without prickles and wings. Petioles 3.5–4.5 cm
long, subterete; sheaths 1.2–1.7 × 0.7–1 cm. Tendrils up to 10.0 cm long, 1.0–1.5 cm above from the base of sheath.
Lamina ovate-oblong to narrowly ovate, (11.0–)15.2–22.4 × (3.5–)5.8–13.6 cm, shiny brownish red to brownish
yellowish on both surfaces when dry or paler and glaucous abaxially, apex acuminate, acumen up to 0.6 cm long, base
cordate, 5-veined, major veins diverging at base of lamina, prominent abaxially, (0.9–)1.7–2.5 cm interval (at widest
point of lamina), connected with reticulate veinlets. Staminate inflorescence composed of spicately disposed umbels,
to 33 cm long, 2–4-branched, rachis slightly zigzagged, not winged; umbels sessile, 22 per inflorescence, 42–54-
flowered, prophylls ovate-lanceolate, 3.0–4.5 × 1.0–1.2 mm, apex acuminate; receptacle of an umbel globose, 2.8 mm
58 Phytotaxa 585 (1) © 2023 Magnolia Press
in diam.; bracteoles 4–5, ovate-triangular to oblong-obovate, 1.6–2.5 × 0.6–1.2 mm, apex acute. Staminate flower
(before anthesis), tepals 6, free from base, outer ones ovate-oblong, 2.5–2.9 × 1.3–1.5 mm, inner ones narrowly ovate,
2.0–2.2 × 0.9–1.0 mm long, apex acute, stamens 6, filaments sessile, anthers oblong, 1.3 mm long; pedicels 0.3–0.7
mm long. Pistillate inflorescence, fruits and seeds not seen.
Distribution:—Thus far known only from the Bolaven Plateau.
Habitat:—Montane forests, 1240–1250 m a.s.l., dominated by Fagaceae, Lauraceae and Myrtaceae, along with
some subcanopy trees such as Taberaemontana bovina (Apocynaceae), Aporosa yunnanensis (Phyllanthaceae), and
Camellia bolavenensis (Theaceae).
Phenology:—Staminate inflorescence with flower buds collected in December.
Etymology:—Referring to the type locality, Bolaven Plateau.
Vernacular name:—Kheau kheaung Bolaven ( ; Lao), suggested here. Kheau kheaung in
Lao refers to a common name for Smilax.
Preliminary conservation assessment:—Critically endangered (CR). During our five intensive field surveys in
Bolaven Plateau 2018–2020, we found only one population with a few individuals in lower montane forest on the top
of a plateau where we collected the above two specimens. Therefore, the most appropriate initial assessment of the
IUCN conservation status for this species is critically endangered (CR) under criteria D (IUCN 2012). In the Bolaven
Plateau, the forests at higher elevation have been decreasing due to dam construction and coffee plantations, which
may produce negative effects for S. bolavenensis. Further information on its distribution and number of individuals/
populations is needed to accurately assess its status and conserve this species.
Note:—Among the Smilax species in Laos, S. bolavenensis resembles S. glabra in leaf texture and venation
patterns, and both species occur in Bolaven Plateau (specimens of S. glabra: Souladeth et al. L3754, FOF, KAG).
However, S. bolavenensis is easily distinguishable from S. glabra by its long-spicately disposed sessile umbels (vs.
only 1 umbel axillary in S. glabra) and its cordate leaf base (vs. cuneate to rounded).
Additional specimen examined:—LAOS. Champasak Province: Paksong District, near Nong Luang Village,
Dong Hua Sao National Park (Bolaven Plateau), 15°04′19.26″N, 106°12′38.67″E, 1248 m a.s.l., 10 Dec 2018, Tagane
et al. L1964 (FOF 005293, FU, KAG 128065).
Authors thank the manager and staff of Dong Hua Sao National Park for permitting our botanical inventories in
the protected area. This study was supported by Nagao Natural Environment Foundation, Japan and partly by JSPS
KAKENHI (21K06307 and 21KK0132).
Baruah, S., Sarma, J. & Borthakur, S.K. (2018) Smilax sailenii (Smilacaceae) – a new species from Assam, North East India. Taiwania
63: 32–36.
Cameron, K.M. & Fu, C.X. (2006) A nuclear rDNA phylogeny of Smilax (Smilacaceae). Aliso 22: 598–605.
Chen, X. & Koyama, T. (2000) Smilacaceae. In: Wu, Z.Y., Raven, P.H. & Hong D.Y. (Eds.) Flora of China, vol. 24. Missouri Botanical
Garden Press, St. Louis and Science Press, Beijing, pp. 96–115. Available from:
(accessed 1 March 2022)
De Candolle, A. & De Candolle, C. (1878) Monographiae phanerogamarum 6: Smilaceae, Restiaceae, Meliaceae. Masson, Paris, 783
Diels, L. (1900) Die Flora von Central-China. Botanische Jahrbücher fur Systematik, Pflanzengeschichte und Pflanzengeographie 29 (2):
Feng, J.Y., Jin, X.J., Zhang, S.L., Yang, J.W., Fei, S.P., Huang, Y.S., Liu, Y., Qi, Z.C. & Li, P. (2022) Smilax weniae, a new species of
Smilacaceae from limestone areas bordering Guizhou and Guangxi, China. Plants 11: 1032.
Gagnepain, F. (1934) Liliacées. In: Lecomte, H. (Ed.) Flore générale de l’Indo-Chine, vol. 6. Masson, Paris, pp. 753−815.
A NEW SPECIES OF SMILAX BOLAVENENSIS Phytotaxa 585 (1) © 2023 Magnolia Press 59
Gagnepain, F. (1934) Deux Liliacées nouvelles. Bulletin de la Société Botanique de France 81: 619.
Heckroth, H.P., Moong, J., Janka, H.I., Fiala, B., Chung, A.Y.C. & Maschwitz, U. (2004) Smilax borneensis (Smilacaceae), an unspecific
climbing ant-plant from Borneo and myrmeophytic traits in other Asiatic Smilax species. Sandakania 14: 33–50.
Hô, P. H. (2000) Cay Co Viet Nam: an illustrated flora of Vietnam, vol. 3. The author, Montreal, 1020 pp.
Hooker, J.D. (1892) Smilax. In: Hooker, J.D. (Ed.) The flora of British India, vol 6, Reeve, London, pp. 302–314.
Jin, X.J., Chen, Y., Lee J., Qi, Z.C., Liu, L.X., Li, Q. & Fu, C.X. (2016) A new species of Smilax (Smilacaceae) from Yunnan, China.
Phytotaxa 275 (2): 159–167.
Kladwong, P. & Chantaranothai, P. (2020) Taxonomic notes on genus Smilax L. (Smilacaceae) from the mainland Southeast Asia. Tropical
Natural History 20: 244–255.
Kladwong, P. & Chantaranothai, P. (2022) Notes on Smilax bockii and S. seisuiensis (Smilacaceae), two newly recorded species from Laos
and Thailand. Thai Forest Bulletin (Botany) 52: 153–160.
Kladwong, P. Chantaranothai, P. & Simpson, D.A. (2018) Two new names and five lectotypfied taxa for the genus Smilax (Smilacaceae)
and the transfer of Smilax petiolatumidus to the genus Dioscorea (Dioscoreaceae). Thai Forest Bulletin (Botany) 46: 44–57.
Koyama, T. (1975) Smilacaceae. In: Smitinand, T. & Larsen, K. (Eds.) Flora of Thailand, vol. 2(3). Applied Scientific Research Corporation
of Thailand, Bangkok, pp. 211–250.
Koyama, T. (1983) Smilacaceae. In: Leroy, Jean-F. (Ed.) Flore du Cambodge, du Laos et du Viêt-Nam, vol. 20. Muséum national d’histoire
naturelle, Paris, pp. 69−124.
Kunth, K.S. (1850) Enumeratio plantarum. Cottae, Stuttgart, 908 pp.
Li, P., Qi, Z.C., Chen, S.C., Cameron, K.M. & Fu, C. (2011) Smilax ligneoriparia sp. nov.: a link between herbaceous and woody Smilax
(Smilacaceae) based on morphology, karyotype and molecular phylogenetic data. Taxon 60: 1104–1112.
Linnaeus, C. (1753) Species plantarum. Salvius, Stockholm, 1200 pp.
Newman, M.F., Pullan, M., Ketphanh, S., Svengsuksa, B., Thomas, P., Sengdala, K., Lamxay, V. & Armstrong, K. (2017 onwards) A
checklist of the vascular plants of Lao PDR. Available from: (accessed 21 February 2022)
Noyori, W., Komada, N., Souladeth, P. & Tagane, S. (2022) Camchaya bolavenensis (Asteraceae: Vernonieae), a new species from Bolaven
Plateau, southern Laos. Phytotaxa 536 (1): 1–6.
Phonepaseuth, P., Souladeth, P., Souvannakhoummane, K., Vongthavone, T. & Tagane, S. (2021) Two new species of Sonerila Roxb.
(Melastomataceae) from Laos. European Journal of Taxonomy 755: 136–148.
POWO (2022) Plants of the World online. Facilitated by the Royal Botanic Gardens, Kew. Available from: http://www.plantsoftheworldonline.
org/ (accessed 1 March 2022)
Profile, E. (2012) Indo-Burma biodiversity hotspot. Update Critical Ecosystem Partnership-Fund, Washington, 360 pp.
Roxburgh, W. (1832) Smilax. In: Roxburgh, W. (Ed.) Flora Indica, vol. 3, Thacker, Serampore, pp. 791–796.
Qi, Z.C., Cameron, K.M., Li, P., Zhao, Y.P., Chen, S.C., Chen, G.C. & Fu, C.X. (2013a) Phylogenetics, character evolution, and distribution
patterns of the greenbriers, Smilacaceae (Liliales), a near-cosmopolitan family of monocots. Botanical Journal of the Linnean
Society 173: 535–548.
Qi, Z.C., Li, P. & Fu, C.X. (2013b) New combinations and a new name in Smilax for species of Heterosmilax in Eastern and Southeast
Asian Smilacaceae (Liliales). Phytotaxa 117 (2): 58–60.
Qi, Z.C., Shen, C., Han, Y.W., Wang, R.H., Liu, R.Z., Naiki, A. & Li, P. (2016) A new species of Smilax (Smilacaceae) from southern island
of Kagoshima prefecture, Japan. Phytotaxa 269 (2): 120–130.
Souladeth, P., Tagane, S., Newman, M.F. & Prajaksood, A. (2020) Two new species of Eriocaulon (Eriocaulaceae) from Laos. Kew
Bulletin 75: 56.
Souvannakhoummane, K., Lanorsavanh, S., Tagane, S., Souladeth, P., Phonpaseuth, P., Pongamornkul, W. & Lamxay, V. (2021) Six new
species and eight new records of Gesneriaceae from Laos. Gardens’ Bulletin Singapore 73: 427–456.
60 Phytotaxa 585 (1) © 2023 Magnolia Press
Sun, Z.Y., Wang, Y.H. Zhao, Y.P. & Fu, C.X. (2015) Molecular, chromosomal and morphological characters reveal a new diploid species
in the Smilax china complex (Smilacaceae). Phytotaxa 212 (3): 199–212.
Tagane, S., Souladeth, P., Kongxaysavath, P., Rueangurea, S., Suddee, S., Suyama, Y., Suzuki, E. & Yahara T. (2020) Two new species and
18 new recrods for the flora of Laos. Thai Forest Bulletin (Botany) 49: 111–126.
Vongthavone, T., Tagane, S., Phonepaseuth, P., Souvannakhoummane, K. & Souladeth, P. (2021) Twelve new records of pteridophytes
from Bolaven Plateau, sothern Laos. Thai Forest Bulletin (Botany) 49: 182–190.
Yamazaki, T., Souladeth, P. & Tagane S. (2021) Strobilanthes bolavenensis, a new species of Acanthaceae from Bolaven Plateau, southern
Laos. Phytotaxa 513 (2): 152–158.
ResearchGate has not been able to resolve any citations for this publication.
Full-text available
Smilax bockii is proposed as an accepted name, and S. septemnervia is treated as a new synonym of S. seisuiensis. Smilax bockii and S. seisuiensis are reported as new records from Laos and Thailand, respectively. The lectotypes of S. bockii and S. stemonifolia are designated. Detailed descriptions, taxonomic notes, photographs and a distribution map are provided.
Full-text available
A new species, Smilax weniae (Smilacaceae), from Southwest China, is described and illustrated. The new species bears peltate leaves, which was previously a unique feature of S. luei. However, it differs from the latter by having a broad ovate leaf blade, longer peduncle, and sexual dimorphic flowers. Further phylogenetic analyses revealed that the new species were placed in a unique position in a subclade of Old World Smilax based on ptDNA and nrITS sequences. Combining detailed morphological comparisons and molecular evidence, we validated that S. weniae is an undescribed new species. Moreover, the plastome characteristics of S. weniae are reported.
Full-text available
A new species Camchaya bolavenensis (Asteraceae: Vernonieae: Centrapalinae) from Dong Hua Sao National Protected Area located in Bolaven Plateau, southern Laos, is described and illustrated. It resembles C. gracilis and C. thailandica in morphology but distinguished by its basally decumbent stem, margin of lamina with distinct (1-)2-3 teeth, 2-4 mm long on each side, invisible secondary veins, and a capitulum with 10-30 of florets.
Full-text available
Two new species of Sonerila Roxb. (Melastomataceae), S. erectifolia Phonep., Soulad. & Tagane sp. nov. from southern Laos, and S. souvannii Phonep. & Soulad. sp. nov. from central Laos, are described and illustrated. Comparisons with morphologically similar species are presented, along with ecological information and preliminary conservation status. A key to the species of Sonerila in Laos is also provided.
Full-text available
Smilax sailenii sp. nov. (Smilacaceae) is described from Assam, north east India based on morphological characteristics observed in the field. Smilax sailenii closely resembles the widespread species Smilax orthoptera A. DC. The detailed morphological features including botanical illustration, photograph, conservation status and key to Smilax sailenii with and related taxa in Assam are provided.
Full-text available
A new species, Smilax hirtellicaulis (Smilacaceae), from southwestern China is described and illustrated. The new species differs from all known Smilax species in its unique tepals, i.e., basally connate in male flowers but separate in female flowers. Phylogenetic analysis supports its species delimitation, and suggests a sister position to the clade of Smilax sect. Heterosmilax which have flowers with connate tepals. Their closest phylogenetic relationship and resembled flower morphology may represent an evolutionary transition from separate to united tepals in Smilax. It thus provides us an ideal model for studying the evolution and development of such an innovative floral trait.
Full-text available
Smilax Linnaeus (1753: 1028) is the only genus of Smilacaceae, comprising ca. 210 species, which are lianas, shrubs, and herbs (Cameron & Fu, 2006; Qi et al. 2013a). The genus shows a near-cosmopolitan distribution (Qi et al. 2013a). In the large genus, Smilax sect. Heterosmilax (Kunth 1850: 270) Judd (1998: 158), formerly treated as an independent genus Heterosmilax Kunth in Smilacaceae, has 12 species and is distributed only in Asian and Malesian regions (Judd 1998, Qi et al. 2013b). All species of the section have slender stem without pricks, cordate leaves, and tendrils in bronze color. Especially, flowers with connate perigone are one of the most important characteristics to distinguish the section from the other sections (Koyama 1984, Qi et al. 2013a).
A new species of Strobilanthes (Acanthaceae), S. bolavenensis, is described from Bolaven Plateau, southern Laos. Photos and illustration are given together with information of habitat, ecology, vernacular name and preliminary conservation assessment based on IUCN criteria.
Two new species of Eriocaulon (Eriocaulaceae), E. cormosum and E. vientianense, from Laos, are described and illustrated. Preliminary conservation assessments and vernacular names are provided.
Smilax asiatica Kladwong, Chantar. & D.A.Simpson and S. goeringii Kladwong, Chantar. & D.A.Simpson are proposed as new names for two later homonyms, S. laevis A.DC. and S. japonica (Kunth) P.Li & C.X.Fu, respectively. Two taxa are reduced to synonymy: S. petiolatumidus B.R.Moore, Narkkong, Th.Moore & Lutat is placed into the synonymy of Dioscorea cirrhosa Lour. and S. zeylanica var. penangensis A.DC. is a new synonym of S. asiatica. Smilax ferox Wall. ex Kunth and S. polyacantha Wall. ex Kunth are newly recorded for Thailand. Smilax asiatica, S. ferox, S. lanceifolia var. opaca A.DC., S. polyacantha and S. zeylanica var. penangensis are lectotypified.