Corresponding author: Yun-Hong Tan (
Academic editor: T. L. P. Couvreur
The genus
Xue B, Ding H-B, Yao G, Shao Y-Y, Fan X-J, Tan Y-H (2020) From
The genus
Amongst the newly segregated genera,
Several species names remain unresolved in
The name
The name
The relationship between these two species has been controversial. Both species are represented by very few collections, with
With limited morphological characters, especially the lack of flowers in
Two accessions of
Six chloroplast DNA regions (
Genomic DNA was extracted from herbarium materials using a modified cetyl trimethyl ammonium bromide (
Sequences were assembled and edited using Geneious ver. 5.4.3 (
Maximum parsimony (
Bayesian analysis was performed using NSF Extreme Science & Engineering Discovery Environment (XSEDE) application of MrBayes ver. 3.2.2 (
Comparative morphological data were obtained from specimens deposited in KUN, IBSC and PE herbaria and from published literature. Field surveys were carried out in Menghai County, Yunnan Province, with voucher specimens deposited in HITBC and IBSC.
The concatenated alignment of the 60-terminal dataset consisted of 7,334 characters. The
The
Bayesian 50% majority-rule consensus tree under partitioned models (cpDNA data:
Although these two species resemble each other vegetatively (Fig.
Morphological comparison between
Morphology of
The monotypic genus
Based on one species with only two collections, the genus is not well described and compared and, hence, it is difficult to identify important diagnostic characters.
In conclusion,
The present phylogenetic study shows that
As
As more species were included in the genus
Medium-sized to large trees. Young twigs glabrous. Leaves petiolate, blade elliptic, with glandular dots observable when dry, base cuneate, apex acute to bluntly (caudate-)acuminate; petiole with transverse striations when dry; upper surface of midrib raised in living plants, becoming slightly sunken when dry, lower surface of midrib raised; secondary veins rather faint in living plants, becoming slightly raised on both sides when dry, leaf venation brochidodromous; tertiary veins reticulate. Flower(s) in 1- to 5-flowered inflorescences, bisexual, pedicellate; inflorescences axillary, peduncle inconspicuous, bracts present. Sepals broadly ovate-triangular. Petals membranous-papyraceous to leathery. Outer petals elliptic-ovate or linear-lanceolate. Inner petals (narrowly) elliptic-ovate or linear-lanceolate. Stamens numerous per flower, connective truncate, covering thecae. Carpels numerous per flower; ovaries with 1 or more line(s) of hairs; stigma terete; ovule(s) 1 or 2 per ovary, sub-basal or lateral. Monocarps oblong to rhomboidal or cylindrical, stipitate, glabrous. Seed(s) 1or 2 per monocarp, cylindrical, surface smooth, raphe broadly sunken and partially slightly raised in middle, endosperm ruminations lamelliform.
Three species, known from Xizang, Yunnan Provinces of China and Thừa Thiên-Hu, Ninh Thuận Provinces of Vietnam (Fig.
China. Xizang: Mêdog, 20 Auguest 1974,
Known from Mêdog in Xingzang Province (Fig.
Flowering in August.
DD (
Trees to 15 m tall (Fig.
Known from several localities in Yunnan Province (Fig.
Distribution of
Flowering in February to March; fruiting from April to July.
China. Yunnan: Kun-man, Xiao-meng-yang, 27 April 1957,
CR A2ac, C2(a)(i) (
1a | Inflorescences 1–5-flowered; petals elliptic-ovate; ovule 1 per carpel; distributed in Vietnam |
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1b | Inflorescences 1–2-flowered; petals linear; ovules 2 per carpel; distributed in China |
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2a | Inflorescences 1–2-flowered; pedicel to 5–7 mm long; flowers green; distributed in Xizang, China |
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2b | Inflorescences with a single flower; pedicel 1–2 mm long; flowers white; distributed in Yunnan, China |
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This research was supported by the National Natural Science Foundation of China [Grant no. 31872646, awarded to Bine Xue and Grant no. 31970223, awarded to Yunhong Tan]; Forestry Scientific Technology Innovation Project of Guangdong Province (No.2020KJCX010); a project of the Lancang-Mekong Cooperation (LMC) Special Fund (Biodiversity Monitoring and Network Construction along Lancang-Mekong River Basin project); the CAS 135 programme [No. 2017XTBG-F03]; and a project supported by the biodiversity investigation, observation and assessment programme (2019–2023) of the Ministry of Ecology and Environment of China. We are grateful to Jing-hua Wang and En-de Liu in KUN and Qin Ban and Xin-tang Ma in PE for permission to access their collections and for permission to use the leaf materials; Ji Mo and Kai-rong Pu for helping in the field in Menghai; Richard Saunders, Daniel Thomas, Thomas Couvreur and an anonymous reviewer for improving the manuscript.
Voucher information and GenBank accession numbers for samples used in this study (–, missing data; *, newly generated sequences). Voucher data are given for accessions for which DNA sequences were newly obtained, using the following format: species, origin, voucher and Genbank accession numbers for