Research Article |
Corresponding author: Jian-Hua Jin ( lssjjh@mail.sysu.edu.cn ) Corresponding author: Wen-Bo Liao ( lsslwb@mail.sysu.edu.cn ) Academic editor: Doug Soltis
© 2019 Wan-Yi Zhao, Kai-Kai Meng, Qiang Fan, Jian-Hua Jin, Wen-Bo Liao.
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:
Zhao W-Y, Meng K-K, Fan Q, Jin J-H, Liao W-B (2019) Saxifraga damingshanensis (S. sect. Irregulares, Saxifragaceae), a new species from Guangxi, China. PhytoKeys 133: 95-103. https://doi.org/10.3897/phytokeys.133.36704
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Saxifraga damingshanensis (Saxifragaceae), a new species from Damingshan Nature Reserve in Guangxi Province, is described and illustrated. A morphological comparison between the new species and its putative relatives, S. mengtzeana and S. luoxiaoensis, is presented. The new species is morphologically similar to S. mengtzeana, but it can be easily distinguished by its non-peltate leaf, both surfaces of mature leaf blade covered with white glandular trichome, petals 3-veined and margin entire. Phylogenetic analysis, based on two chloroplast DNA regions (matK and psbA-trnH), confirmed that the new species belongs to S. sect. Irregulares. The new species is currently only known from Damingshan, Guangxi and we assign it an IUCN Red List preliminary status as Data Deficient.
China, chloroplast gene, phylogeny
Saxifraga L. (Saxifragaceae) is widely distributed throughout the Northern Hemisphere and comprises ca. 440–450 species (
In China, Saxifraga comprises 216 species, of which seven species belong to S. sect. Irregulares, according to the "Flora of China" (
During a botanical expedition to Damingshan National Nature Reserve, Wuming district, central Guangxi Province in September 2018, we discovered an unknown species of Saxifraga in Longtou Peak. Its mature leaves are densely covered with white trichomes and the abaxial surface is densely purple-spotted. After carefully checking specimens and literature, as well as morphological and molecular studies, we confirm that it is a new species of Saxifraga and it is described below.
We collected more than 20 living individuals of the presumed new species for comparisons and taxonomical treatment. Specimens of Saxifraga sect. Irregulares, available at herbaria (PE, IBSC, SYS and IBK) and digital photos of all herbarium specimens of S. luoxiaoensis, S. mengtzeana Engl. & Irmsch., preserved in the Chinese Virtual Herbarium (http://www.cvh.org.cn/), have been checked. Five main characters (leaf shape, leaf margin, spots on the abaxial surface of leaf, petal shape and trichomes on plants) of these three species were compared both in the wild and in the herbarium.
To determine the systematic position of Saxifraga damingshanensis, we further sampled five individuals of the presumed new species for a phylogenetic study. The geographic sampling information of these individuals was recorded by a Garmin GPS unit (GPSMAP 62sc, Taiwan) and the voucher specimens were deposited at Sun Yat-sen University Herbarium (SYS) (Table
Voucher information and GenBank accession numbers for sequence data of Saxifraga damingshanensis phylogenetic analysis used in this study.
Species | Voucher | matK | psbA-trnH2 |
---|---|---|---|
Saxifraga damingshanensis | W. Y. Zhao 1208; Damingshan, Guangxi | MK976729 | MK976724 |
W. Y. Zhao 1209; Damingshan, Guangxi | MK976730 | MK976725 | |
W. Y. Zhao 1210; Damingshan, Guangxi | MK976731 | MK976726 | |
W. Y. Zhao 1211; Damingshan, Guangxi | MK976732 | MK976727 | |
W. Y. Zhao 1212; Damingshan, Guangxi | MK976733 | MK976728 | |
Saxifraga mengtzeana | FHZ-1608; Yuanbao Mountion, Guangxi | MK092518 | – |
Saxifraga rufescens | YLDP197D; Yulong Mountion, Yunnan | MH116857 | MH117313 |
Saxifraga stolonifera | LXP-13- 24775(1); Yanling country, Hunan | MK092557 | MK092599 |
LXP-13- 24775(2); Yanling country, Hunan | MK092558 | MK092600 | |
LXP-13- 24775(3); Yanling country, Hunan | MK092551 | MK092593 | |
LXP-13- 24775(4); Yanling country, Hunan | MK092552 | MK092594 | |
Saxifraga epiphylla | Q. Fan 15680(1); Qingchengshan, Sichuan | MK092519 | – |
Q. Fan 15680(2); Qingchengshan, Sichuan | MK092520 | – | |
Saxifraga daqiaoensis | RY-2017-031(1); Daqiao Town, Guangdong | MK092533 | MK092575 |
RY-2017-031(2); Daqiao Town, Guangdong | MK092534 | MK092576 | |
Saxifraga luoxiaoensis | LXP-13-24717(1); Nanfengmian, Jiangxi | MK092539 | MK092581 |
LXP-13-24717(2); Nanfengmian, Jiangxi | MK092540 | MK092582 | |
Saxifraga shennongii | LXP-13-24778(1); Yanling country, Hunan | MK092527 | MK092569 |
LXP-13-24778(2); Yanling country, Hunan | MK092528 | MK092570 | |
LXP-13-24769(1); Yanling country, Hunan | MK092521 | MK092563 | |
LXP-13-24769(2); Yanling country, Hunan | MK092522 | MK092564 |
The total DNA was extracted with the modified CTAB method (
In morphology, the putative new species is closely related to Saxifraga mengtzeana and their morphology comparisons are presented in Table
Morphological comparisons amongst Saxifraga damingshanensis, S. luoxiaoensis and S. mengtzeana.
Characters | Saxifraga damingshanensis | S. luoxiaoensis | S. mengtzeana |
---|---|---|---|
Leaf shape | rounded or ovate, never peltate | reniform, never peltate | ± peltate, ovate |
Leaf texture | papery or leathery | papery | leathery |
Leaf base | cordate to deep cordate | cordate | ± cordate |
Leaf margin | 5–10-lobed, lobes entire, sparsely glandular hairy | margin 7–9-lobed, usually double serrate | crenate, inconspicuous glandular hairy |
Abaxial surface of leaf blade | with glandular trichome and purple spots | glabrous with red or brown spotted | sparsely hispid and brown spotted |
Second longest petal | lanceolate oblong, 13–17 × 2 mm, 3-veined | lanceolate oblong, ca. 8–20 mm × 1.3–3 mm, 3−5-veined | narrowly ovate, ca. 9 × 2.2 mm, 3-veined |
First longest Petal | lanceolate, 1.8–2.2 cm × 1.5–2.5 mm, 3-veined, margin entire | linear lanceolate, 16–25 mm × 1.3 − 3 mm, 3–5-veined, margin entire | sublanceolate, 19 × 3.4 mm, 8-veined, margin sparsely denticulate |
Stamens | 3.5–4.5 mm long | 4.3–5.6 mm long | ca. 6 mm long |
Flowering period | August to October | April to June | May to August |
The concatenated sequences of matK (740 bp) and psbA-trnH2 (297 bp) are 1037 bp in length and 81 parsimony-informative sites were detected. Our results showed that S. ser. Rufescentes J.T.Pan is monophyletic (SH-aLRT: 100; LP: 100; PP: 1.00, Fig.
Bayesian consensus tree of Saxifraga damingshanensis and related species derived from two chloroplast regions. Numbers above branches are the value of SH-like approximate likelihood ratio test (aLRT) and bootstrap value of the Maximum Likelihood (LP); numbers below branches indicate Bayesian posterior probability (PP). Asterisks denoted (*) the values of 100 or 1.00 for LP/PP. The new species is shown in bold.
Based on its basal leaves with long petiolate, flower zygomorphic and stamens with club-shaped filaments, the new species could be placed within S. sect. Irregulares. Our phylogeny also supports the inclusion of Saxifraga damingshanensis within S. sect. Irregulares (Fig.
Our study also recovered a sister relationship of the new species with a clade comprising Saxifraga luoxiaoensis, S. daqiaoensis and S. shennongii. The close relationship amongst these species was also supported by their similar morphological characteristics. All four species have white glandular trichomes on leaf and inflorescence and white and entire petals. However, S. damingshanensis differs from the latter three species by having mature leaf and petiole with glandular trichomes (vs. mature leaf sparsely hispid or glabrous) and the abaxial surface of the leaf blade with purple spots (vs. usually yellow-brown spots). Furthermore, their phenology and distribution are different. Saxifraga damingshanensis is flowering from August to October (vs. April to June) and endemic to Damingshan, Guangxi (vs. Guangdong, Jiangxi and Hunan).
China. Guangxi: Nanning city, Damingshan Nature Reserve, Longtou Peak, 23°22'58.48"N, 108°30'21.56"E, 1542 m alt., 19 September 2018, W.Y.Zhao 1208 (Holotype SYS!; Isotypes SYS!, IBSC!). (Fig.
Saxifraga damingshanensis is morphologically most similar to S. mengtzeana, but differs by its leaf blade with glandular trichome and purple spots abaxially, short stamens and petal entire.
Perennial herbs, 15–30 cm tall. Stolons absent. Rhizomes rather short (ca. 0.3–0.7 cm), sparsely glandular trichomes. Basal leaves forming a rosette, petiole 5–15 cm long, fleshy and translucent, sparsely short glandular trichomes (ca. 2 mm); petiole base sheathed, margin with sparsely glandular trichomes; leaf blade rounded or ovate, base cordate to deep cordate, papery or leathery, 2.0–5.7 × 2.5–5.5 cm, apex obtuse, margin inconspicuous 7–15-lobed with sparsely glandular trichomes, lobes entire, adaxially dark green, densely covered glandular trichomes (2.5–4 mm), abaxially grey, sparsely covered with glandular trichomes (1.5–2.5 mm), densely covered with purple spots; palmate veins 7–11, both surfaces inconspicuous. Cauline leaves 1–2, triangular-lanceolate, 5.0–6.0 × 1.5–2.0 mm, margin with sparsely glandular trichomes. Inflorescence paniculate, 15–30 cm long, 10–35-flowered; branches 4–5 cm, sparsely short glandular trichomes (0.5–1.0 mm), 2–6(-8)-flowered; pedicels slender, 1.5–2.5 cm long, sparsely short glandular trichomes (ca. 0.5 mm); bracts linear, 1.5–2.5 × 0.5–0.8 mm, margin with short glandular trichomes. Flowers zygomorphic; sepals 5, spreading, narrowly ovate, 2.0–2.5 × 1.0 mm, apex obtuse, base connate, adaxially glabrous, abaxial surface and margin with sparsely short glandular trichome, becoming denser proximally, 3 veins inconspicuous. Petals 5, white; shortest 3 petals equal, ovate, base with yellow spots, 3–3.5 × 1.5 mm, apex acute, base rounded, triplinerved; the other two petals lanceolate, first longest petal lanceolate, 18–22 × 1.5–2.5 mm, apex acuminate, margin entire, glabrous, 3-veined; second longest petal narrowly ovate, 1.3–1.7 × 0.2 cm, apex acuminate, margin entire, glabrous, 3-veined. Stamens 10, filaments clavate, 3.5–4.5 mm long. Ovary ovoid, 1.5–2.5 mm long; disc obscure; carpels 2, proximally connate about 3/4; styles 2, divergent, 1.5–2 mm long. Capsule ovoid, 4–5 × 3–4 mm. Seeds elongate-ellipsoid, yellowish-brown or dark brown, the two ends slightly bent, ca. 0.6 mm, surface 3-ribbed.
Flowering from August to October, fruiting from September to November.
The species epithet is based on the mountain name, Damingshan and the Latin suffix, -ensis, of origin, where the new species was collected.
Only three populations of Saxifraga damingshanensis were discovered from Damingshan National Nature Reserve, Guangxi Province. It was observed to grow on damp cliffs and rocks in broad-leaved forests at altitudes between 1300 and 1650 m. Its known localities are well protected and more field investigations are needed to determine its wild distribution. Therefore, we suggest listing the new species as Data Deficient (DD) based on the IUCN Red List Criteria (
China. Guangxi: Nanning city, Damingshan Nature Reserve, Longtou Peak, Blackwood cliff, 23°22'58.48"N, 108°30'21.56"E, 1542 m alt., 19 September 2018, W.Y.Zhao 1209 (SYS!); same locality, 1500 m alt., 19 September 2018, W.Y.Zhao 1210 (SYS!); same locality, 1522 m alt., 19 September 2018, W.Y.Zhao 1211 (SYS!); same locality,1480 m alt., 19 September 2018, W.Y.Zhao 1212 (SYS!); Wuming county, Xiaolu village, Damingshan, 1420 m alt., 26 August 1958, Y.C.Chen 325 (IBK18155!).
Saxifraga damingshanensis A Habit B whole plant C basal leaves rosette with long petiole, plant cover white trichomes D flower and fruit, pedicel slender with short trichomes, filaments clavate E adaxial leaf surface dark green, sparsely glandular piliferous F abaxial leaf surface grey, sparsely glandular piliferous and purple spotted G petiole with glandular piliferous H rhizomes cover sparsely glandular piliferous, petiole base sheathed I adaxial surface of sheath, glabrous, margin with glandular piliferous J abaxial surface of sheath, upper with sparse glandular piliferous.
We thank Fan Ye and Bao-Huan Wu for the field work. We thank Su-Juan Wei and Ping Yang for providing images of herbarium specimens in IBK. We are grateful to Ke-Wang Xu and two reviewers for the valuable comments and suggestions on the manuscript. This study was supported by the Basic Work Special Project of the National Ministry of Science and Technology of China (2013FY111500) and the project of the Fourth Survey of Chinese Traditional Medicine Resources (2018-523-001).