Research Article |
Corresponding author: Ying Liu ( liliumrosa@163.com ) Academic editor: Ricardo Kriebel
© 2019 Jin-Hong Dai, Qiu-Jie Zhou, Zhi-Yong Yu, Ren-Chao Zhou, 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, Zhou Q-J, Yu Z-Y, Zhou R-C, Liu Y (2019) A new species of Fordiophyton (Sonerileae, Melastomataceae) from Yunnan, China. PhytoKeys 122: 15-28. https://doi.org/10.3897/phytokeys.122.35260
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Fordiophyton jinpingense (Melastomataceae; Sonerileae), a species occurring in south-eastern Yunnan, China, is described as new, based on morphological and molecular data. Phylogenetic analyses, based on nrITS sequence data, showed that, except F. breviscapum, all species sampled in Fordiophyton formed a strongly supported clade in which two geographical lineages were recovered. The generic placement of F. jinpingense is well supported by phylogenetic analyses and a character combination of 4-merous flowers, distinctly dimorphic stamens and the connectives basally not calcarate. Molecular divergence and morphological evidence indicate that F. jinpingense is well separated from other members of the genus, thus justifying its recognition as a distinct species. Fordiophyton jinpingense is phylogenetically closest to F. repens, but differs markedly from the latter in stem morphology (short, obtusely 4-sided vs. long, 4-angular), habit (erect vs. creeping), leaf size (6–16.5 × 4.5–13 cm vs. 4–7.5 × 4–6.5 cm) and flower number per inflorescence (5–13 vs. 3–6).
Fordiophyton, Melastomataceae, taxonomy, phylogeny
In the study of Asian Sonerileae, Stapf established two new genera, Fordiophyton Stapf and Gymnagathis Stapf, based on three species in China (
Fordiophyton, as currently defined, is a small Asian genus of 13 species mainly occurring in southern China, with only one species extending to northern Vietnam (
Flowers of Fordiophyton showing anther morphology of the longer stamens. A F. peperomiifolium from Qingyuan, Guangdong, China, anther base not forked B F. faberi from Hengshan, Hunan, China, anther base forked C F. strictum from Pingbian, Yunnan, China, anther base forked and curved. Arrows indicate the anther base of the longer stamens.
During a field survey, we encountered a distinct plant in the forests of Ma-an-di, Fenshuiling National Nature Reserve in Jinping County, south-eastern Yunnan. This plant had eight distinctly dimorphic stamens and connectives not calcarate at the base, which are typical characteristics of Fordiophyton. It was distinct from all known species of Fordiophyton in the combination of short stems with distinct internodes, basal rosette of leaves, unwinged, densely villous petioles, umbellate inflorescence and anther base of longer stamens distinctly forked and curved (Figs
To evaluate the specific status and phylogenetic position of this species in Fordiophyton, phylogenetic analyses were performed, based on DNA sequence data of the nuclear ribosomal internal transcribed spacer (nrITS). The results confirmed our suspicions that these plants represented a previously unrecognised species, F. jinpingense, which we describe below as new. A key to separate it from other species of Fordiophyton is also provided.
Fordiophyton jinpingense, all from Y. Liu 728 (SYS, A). A Habitat B a flowering individual C adaxial leaf surface D abaxial leaf surface E petiole villous with multiseriate hairs F young inflorescence G young inflorescence dissected showing the position and morphology of bracts. Scale bar: 2 cm (G).
Detail of inflorescence, flower, stamens, ovary and fruit of Fordiophyton jinpingense, all from Y. Liu 728 (SYS, A). A Mature inflorescence B side view of a flower C top view of a flower D longitudinal section of a flower showing dimorphic stamens and ovary crown E anther morphology in detail F transection of ovary at young fruit stage, showing the very short-stalked, nearly sessile placenta G young fruit showing the crown not exserted from hypanthium. Scale bars: 5 mm (D–F).
For phylogenetic analyses, the nrITS sequences of F. longipes and F. jinpingense were newly sequenced, while the sequences of other species were downloaded from GenBank. The final dataset contained 131 accessions representing 106 species and three varieties from 19 genera in Sonerileae/Dissochaeteae and one in tribe Blakeeae. Blakea schlimii (Naudin) Triana was selected as an outgroup according to previous studies (
Total DNA was extracted from fresh leaves using the modified CTAB procedure (
Sequences were aligned using SeqMan v.7.1.0 (DNASTAR Inc., Madison, WI). The best-fitting nucleotide substitution model was determined using the Akaike Information Criterion in Modeltest version 3.7 (
The aligned sequence matrix contained 766 characters. Statistics of sequences sampled are summarised in Suppl. material
Phylogenetic relationships amongst species of Fordiophyton. Part of the Maximum Likelihood (ML) phylogenetic tree based on nrITS sequence data. Numbers above branches are bootstrap values obtained from maximum likelihood analyses, and those below branches are Bayesian posterior probabilities (right) and bootstrap values (left) resulting from maximum parsimony analyses. Box denotes the new species; asterisk denotes a branch collapsed in Bayesian inference or maximum parsimony analyses.
Phylogenetic analyses recovered two subclades in the Fordiophyton clade (Fig.
The currently circumscribed Fordiophyton is not monophyletic, as F. breviscapum appears to be related to Phyllagathis tetrandra and P. elattandra, rather than to other members of the same genus. Fordiophyton breviscapum is morphologically most closely related to F. degeneratum (C. Chen) Y. F. Deng & T. L. Wu, which was not included in the phylogenetic analyses. These two species, as well as P. tetrandra and P. elattandra, have been treated in Stapfiophyton (
Fordiophyton damingshanense S. Y. Liu & X. Q. Ning is another species which was not sampled in previous and present phylogenetic studies. It highly resembles F. faberi in habit, leaf morphology and stamen morphology. Geographically, it occurs in Guangxi, where F. faberi also occurs. Morphology and distribution imply that F. damingshanense is probably a member of subclade 1.
Stamen number and morphology of Fordiophyton breviscapum, Phyllagathis elattandra and P. tetrandra. A F. breviscapum from Ruyuan, Guangdong, China, 8 stamens with the shorter stamens greatly reduced B P. elattandra from Guiping, Guangxi, China, 8 stamens with the shorter stamens sterile C P. tetrandra from Xichou, Yunnan, China, 4 stamens. Arrows indicate anther of the shorter stamens.
The generic placement of F. jinpingense is supported by morphological and phylogenetic data. Its 4-merous flowers, eight distinctly dimorphic stamens and the connectives basally not calcarate fit perfectly well with the morphological circumscription of Fordiophyton. Phylogenetic analyses also showed that F. jinpingense was nested within the same clade, together with the type of Fordiophyton, F. faberi.
At the molecular level, pairwise sequence divergence at the nrITS region between F. jinpingense and other species of Fordiophyton ranges from eight to 42 nucleotide substitutions, which is equivalent to the number of substitutions between other species of Fordiophyton (ranging from 14 to 47 nucleotide substitutions). Molecular divergence, therefore, indicates that F. jinpingense is well diverged from other members of the genus. Morphologically, the basal rosette of leaves of F. jinpingense makes it quite distinct from species with erect, leafy stems, viz. F. cordifolium, F. faberi, F. longipes and F. strictum. It closely resembles F. brevicaule, F. chenii, F. huizhouense, F. peperomiifolium and F. zhuangiae in habit, but differs from F. chenii and F. zhuangiae in the unwinged, villous petioles (vs. winged and glabrous), from F. huizhouense and F. peperomiifolium in stems with distinct internodes (vs. indistinct) and from F. brevicaule in longer petioles (3–16 cm vs. 1–3 cm), larger leaf blades (6–16.5 × 4.5–13 cm vs. 3.5–8 × 2–5 cm) and umbellate inflorescence (vs. cymose paniculate). In fact, the phylogenetic analyses showed that F. jinpingense is most closely related to F. repens rather than to the above species. Fordiophyton repens is narrowly endemic to Pingbian County, south-eastern Yunnan. The two are similar in having villous petiole and leaf blade, umbellate inflorescence and anther base of longer stamens forming a forked spur. Nevertheless, they differ markedly in stem morphology (short, obtusely 4-sided vs. long, 4-angular), habit (erect vs. creeping) (Fig.
CHINA. Yunnan: Jinping County, Ma-an-di town, 900–1900 m alt., damp but well drained places in forest, 10 Mar 2019, Ying Liu 728 (holotype: A; isotype: SYS).
Differs from F. repens in having slightly obtusely 4-sided short stem (vs. 4-angular, long and creeping), mature leaves 6–16.5 × 4.5–13 cm (vs. 4–7.5 × 4–6.5 cm) sparsely and shallowly dentate leaf margin with each tooth having a caducous terminal seta (vs. densely denticulate, persistent) and inflorescence 5–13-flowered (vs. 3–6-flowered).
Perennial herbs, 10–14 cm tall (including inflorescence). Stems 2–5 cm long, slightly obtusely 4-sided, sometimes branched, villous with multiseriate hairs. Petiole 3–16 cm long, densely villous with multiseriate hairs; leaf blade ovate-oblong to ovate-orbicular, 6–16.5 × 4.5–13 cm, papery, adaxially green to dark green, abaxially pale green or sometimes purplish-red, villous with multiseriate hairs on veins, both surfaces inconspicuously pubescent with very short, appressed uniseriate hairs, secondary veins 3 or 4 on each side of midvein, base cordate, margin sparsely and shallowly dentate with each tooth having a terminal seta when young but caducous at maturity, apex short acute, obtuse or retuse. Inflorescences terminal and axillary, umbellate, 5–13-flowered; peduncle 9–14 cm long, sometimes white maculate, bearing several multiseriate hairs at nodes, otherwise glabrous; bracts caducous, oblong, 1–3 cm long, one pair (rarely two) in middle or lower part and another two pairs enclosing the flowers. Pedicels 4–10 mm long, glabrous. Hypanthium funnel-shaped, ca. 10 mm long, obtusely 4-sided, glabrous. Calyx lobes narrowly triangular-ovate, 2–5 × 1–2 mm, margin entire, apex obtuse or acute, caducous. Petals pink, obovate, ca. 16 × 8 mm, oblique. Longer stamens pink; filaments ca. 9 mm; anthers ca. 13 mm long, linear, curved, base lengthened into a forked, curved spur, connective bulging basally. Shorter stamens yellowish; filaments ca. 6 mm long; anthers oblong, 3–4 mm long, base obtusely forked, connective base slightly bulging. Ovary obovate, apex with a membranous ciliate, 4-lobed crown. Capsule funnelform-campanulate, ca. 6 mm in diam., apex 4-lobed, crown not exserted from calyx; hypanthium exceeding capsule, glabrous. Seeds numerous.
Flowering March–April, fruiting April–May.
The specific epithet is derived from Jinping County, the type locality of Fordiophyton jinpingense.
1 | Leaves in a basal or sub-basal rosette | 2 |
– | Leaves cauline | 7 |
2 | Petiole winged and glabrous | 3 |
– | Petiole unwinged, densely or sparsely hairy | 4 |
3 | Petioles 8–18 cm long; leaf blade 9–13 × 9–12 cm; secondary veins 4 on each side of midvein; hypanthium and calyx lobes hairy | F. chenii |
– | Petioles 2–4 cm long; leaf blade 4–9 × 2–4 cm; secondary veins 2 or 3 on each side of midvein; hypanthium and calyx lobes glabrous | F. zhuangiae |
4 | Internodes of stems distinct | 5 |
– | Internodes of stems indistinct | 6 |
5 | Internodes glabrous; petioles 1–3 cm long; leaf blade 3.5–8 × 2–5 cm; inflorescence cymose-paniculate; anthers of longer stamens forming an obtuse forked spur at base | F. brevicaule |
– | Internodes hairy; petioles 3–16 cm long; leaf blade 6–16.5 × 4.5–13 cm; inflorescence umbellate; anthers of longer stamens forming a forked, curved spur at base | F. jinpingense |
6 | Hypanthium glabrous; calyx lobes lanceolate, 6 × 2 mm; base of connective of longer stamens prolonged | F. huizhouense |
– | Hypanthium sparsely hairy; calyx lobes triangular, 1 × 2 mm; base of connective of longer stamens not prolonged | F. peperomiifolium |
7 | Stem creeping | F. repens |
– | Stem erect or at least erect in upper part | 8 |
8 | Stem less than 20 cm long | 9 |
– | Stem more than 30 cm long | 10 |
9 | Stem winged; secondary veins 1 on each side of midvein; inner 4 stamens fertile | F. breviscapum |
– | Stem not winged; secondary veins 3 or 4 on each side of midvein; inner 4 stamens sterile | F. degeneratum |
10 | Leaves of a pair highly unequal and asymmetric; petioles often less than 1 cm long; bracts cordate, ca. 4 mm long | F. strictum |
– | Leaves of a pair equal or slightly unequal; petioles more than 2 cm long; bracts more or less ovate, often more than 1 cm long | 11 |
11 | Leaf blade cordate to ovate-cordate, secondary veins 4 or 5 on each side of midvein | F. cordifolium |
– | Leaf blade broadly lanceolate, oblong, ovate, oblong-lanceolate to elliptic; secondary veins 2 or 3, rarely 4 (F. damingshanense) on each side of midvein | 12 |
12 | Inflorescences umbellate, peduncle winged | F. longipes |
– | Inflorescences cymose-paniculate, umbellate or a pleiochasium, peduncle not winged | 13 |
13 | Inflorescences cymose-paniculate, umbellate, 13–20 cm long | F. faberi |
– | Inflorescences pleiochasia, ca. 10 cm long | F. damingshanense |
We thank Ms. Xiao-Lan Wang for providing the photo of F. faberi, Dr. David E. Boufford for his valuable comments on the manuscript and the staff of Fenshuiling National Nature Reserve for their help in the field. This work was supported by the National Natural Science Foundation of China (31770214) and the Science and Technology Planning Project of Guangdong Province (2015A030302011).
Table S1. Source of materials studied and GenBank accession numbers for nrITS
Data type: molecular data
Explanation note: Newly generated sequences are indicated in bold.
Table S2. Summary statistics of sequences used for phylogenetic analyses
Data type: phylogenetic analyses
Explanation note: PIS, parsimony-informative sites.
Figure S1. Maximum likelihood phylogenetic tree of Sonerileae based on nrITS sequences.
Data type: Figure
Explanation note: Numbers above branches are bootstrap values obtained from maximum likelihood analyses and those below branches are Bayesian posterior probabilities (right) and bootstrap values (left) resulting from Bayesian inference and maximum parsimony analyses, respectively. Species of Fordiophyton are indicated in bold; box denotes the new species; asterisk denotes a branch collapsed in Bayesian inference or maximum parsimony analyses.