Research Article |
Corresponding author: De-Zhu Li ( dzl@mail.kib.ac.cn ) Academic editor: Eduardo Ruiz-Sanchez
© 2020 Xia-Ying Ye, Yu-Xiao Zhang, De-Zhu Li.
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:
Ye X-Y, Zhang Y-X, Li D-Z (2020) Two new species of Fargesia (Poaceae, Bambusoideae) from southwestern China. PhytoKeys 170: 25-37. https://doi.org/10.3897/phytokeys.170.58780
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Two new species of Fargesia, one from Xizang (Tibet) and one from Yunnan, China, are described and illustrated. Fargesia viridis D.Z. Li & X.Y. Ye is characterized by its densely white powder, nearly solid internodes, yellow setose sheath scar and culm sheaths, and 4–6 leaves of large size. Fargesia purpurea D.Z. Li & X.Y. Ye has thinner culms (0.5–1.4 cm in diameter), a ring of 4–5 mm tall brown setae below nodes, fewer branches, glabrous sheath scar and culm sheaths, differentiated from the related species.
Fargesia, new species, southwestern China, taxonomy, temperate woody bamboos
Tribe Arundinarieae, i.e. the temperate woody bamboos, is one of the three tribes of the subfamily Bambusoideae (Poaceae), containing approximately 581 species in 31 genera (
Among the 31 genera, Fargesia Franchet is the largest one, consisting of more than 90 species (
Fargesia is characterized by the presence of short-necked pachymorph rhizomes (usually < 20 cm), unicaespitose clumps, 7–15 branches at mid-culm nodes, semelauctant inflorescence, racemose to paniculate, compressed or open, with 3 stamens (
Although flowering is not frequent in this genus, it shows considerable diversity in vegetative morphology and many new species continue to be described (
Observation and measurement of morphological characters were undertaken using living plants in the field and specimens in the lab. Morphological features of related species were obtained from specimens and literature (
Fargesia viridis D.Z. Li & X.Y. Ye resembles F. frigidis Yi, F. zayuensis Yi and F. similaris Hsueh & Yi, but can be distinguished from F. frigidis by thinner and glabrous culm, more leaves on the ultimate branch, longer leaf sheath and large leaf blade, from F. zayuensis by shorter and thinner culm, solid internode, more leaves on the ultimate branch and broader leaf blade, and from F. similaris by solid internode, prominent sheath scar, setose culm sheath, glabrous petiole, more leaf number and larger leaf blade.
China, Yunnan, Gongshan County, along the road to Dulongjiang Town, 27°51'28"N, 98°26'46"E, 2667 m alt., 1 September 2015, X.Y.Ye YXY272 (holotype & isotype: KUN!).
Rhizomes pachymorph, rhizome neck 3–6 cm long, 1–1.6 cm in diameter, solid. Culms 2–3 (4) m tall, pluricaespitose, 0.6–1.2 cm in diameter; internodes terete, 16–22 (30) cm long, densely white powdery and black when culms old, glabrous, nearly solid; nodes with weakly prominent supra-nodal ridge; sheath scar prominent, initially brown setose, with persistent remains of sheath base. Branches 8–10, fascicular, open; buds oblong, margins yellow-brown ciliolate. Culm sheaths persistent or tardily deciduous, leathery, narrowly rounded, 1/3 as long as internodes, yellow setose, densely at base and readily deciduous, longitudinal ribs prominent, margins yellow ciliolate, apex asymmetrical; auricles absent; oral setae absent or 1–2, ca. 2 mm long; ligule concave or truncate, ca. 1 mm tall, glabrous, fissured; blades erect or reflexed, linear-lanceolate, glabrous, narrower than the apex of culm sheath. Foliage leaves 4–6 per ultimate branch; sheath 3–4 cm long, glabrous, purple, margins ciliolate; auricles and oral setae absent; ligule truncate, ca. 1 mm tall; petiole 1–3 mm long, glabrous; blade lanceolate, 4–9 × 0.7–1.4 cm, glabrous, base broadly cuneate, secondary veins 2–3 pairs, transverse veins conspicuous, margins serrate. Inflorescence unknown.
New shoots July to August.
The specific epithet refers to the beautiful color of leaf blade.
Cuì Lǜ Jiàn Zhú (Chinese pronunciation); 翠绿箭竹 (Chinese name).
Fargesia viridis is only known from the type locality, the Dulongjiang Town. It occurs along the stream and grows as pure bamboo forest or under the evergreen broadleaved forest at an elevation of 2600–2800 m alt.
Morphological comparisons between Fargesia viridis and the related species were provided in Table
Characters | Fargesia viridis | Fargesia frigidis | Fargesia zayuensis | Fargesia similaris |
---|---|---|---|---|
Culm height | 2–3 (4) m | 1.5–3.5 m | 6 m | Shrubby |
Culm diameter | 0.6–1.2 cm | 1–1.7 cm | 0.8–1.5 cm | 0.8–1.2 cm |
Internode | 16–22 (30) cm long, densely white powdery, glabrous, nearly solid | 22–24 cm long, initially densely white waxy and white-gray setose below nodes, glabrescent, nearly solid | 25–35 cm long, initially sparsely white powdery; hollow, wall 1.5–2 mm thick | 9.5–18.2 cm long, white or black powdery below nodes, wall 2–3 mm thick, cavity filled with lamellate pith |
Branch complement | 8–10 | 4–13 | 5–10 | 3–8(15) |
Sheath scar | Prominent, initially yellow setose, with persistent remains of sheath base | Very prominent, woody | Prominent | Weakly prominent |
Culm sheath | Persistent or tardily deciduous, yellow setose and densely at base, readily deciduous, longitudinal ribs prominent, margins yellow ciliolate, apex asymmetrical | Gradually deciduous to persistent, very sparsely appressed light yellow setulose, upper margins yellow-‐brown ciliolate initially, longitudinal ribs conspicuous, apex asymmetrical |
Gradually deciduous, abaxially slightly gray-brown setulose, margins brown ciliolate or not | Glabrous, margins densely ciliolate, apex slightly white powdery |
Culm sheath oral setae | Absent or 1–2, 2 mm long | Absent | Readily deciduous | Absent or 1–3 |
Culm sheath ligule | Concave or truncate, ca. 1 mm | Convex or truncate, 1–1.5 mm, glabrous | Truncate, ca. 1 mm | Truncate, ca. 1 mm |
Culm sheath blade | Erect or reflexed, triangular or linear-lanceolate | Reflexed, readily deciduous, triangular to linear-lanceolate | Readily deciduous, reflexed, rarely erect, linear-lanceolate | Erect, triangular-conical, glabrous |
Leaf number of the ultimate branch | 4–6 | 1–4 | 1–3 | 2–4 |
Leaf sheath | 3–4 cm long, glabrous | 1.5–2 cm long, glabrous | 3–4 cm, glabrous | Glabrous or with white pubescent margins |
Leaf oral setae | Absent | Absent or sometimes few | Absent | 2–6, 2–4 mm long, yellow-brown or gray |
Leaf ligule | Truncate, ca. 1 mm | Inclined- truncate, ca. 0.4 mm | Truncate, glabrous | Truncate, ca. 1 mm |
Petiole | 1–3 mm long | 1 mm long | 1 mm long | Sparely gray-white pubescent |
Leaf blade | 4–9 × 0.7–1.4 cm, glabrous, secondary veins 2–3 pairs | 2.3–5.2 × 0.45–0.7 cm, glabrous, secondary veins 2 or 3 pairs | 5–8.5 × 0.4–0.6 cm, glabrous, secondary veins 2 pairs | 1.3–6.5 × 0.4–0.6 cm, glabrous or abaxially white-gray pubescent, secondary veins 2- or 3 paired |
Habitat | Along the stream or under the evergreen broadleaved forest at the altitude of 2600–2800 m, northwest, Yunnan. | On the shady slope of barren hills at 3100–3700 m, west Yunnan. | Under the Pinus or broadleaved forest, 2500–3000 m, Zayu, Xizang (Tibet). | Unknown, Yunnan |
Fargesia purpurea D.Z. Li & X.Y. Ye resembles F. pauciflora (Keng) Yi and F. brevistipedis Yi, but can be distinguished from the former by thinner and taller culms, a ring of 4–5 mm tall brown setae below nodes, glabrous sheath scar, fewer branches and more leaf number, from the latter by a ring of 4–5 mm tall brown setae below nodes, less branch number, glabrous sheath scar, oral setae absent and narrower leaf blade.
China, Xizang (Tibet), Zayu County, Xiachayu Town, bamboo mountain of new village, 28°31'14"N, 96°57'59"E, 2705 m alt., 24 August 2015, X.Y.Ye & X.He YXY254-1 (holotype & isotype: KUN!).
Rhizomes pachymorph, rhizome neck 5–10 cm long, 1.2–2 cm in diameter, solid. Culms (3)4–5(6) m tall, unicaespitose, 0.5–1.4 cm in diameter; internodes terete, 30–46 cm long, white powdery and black when culms old, with a ring of 4–5 mm brown setae below nodes, longitudinal ribs prominent; wall 1–4 mm thick, cavity filled with lamellate pith; nodes with weakly prominent supra-nodal ridge; sheath scar prominent, with persistent remains of sheath base. Branches 3–7, open; buds triangular. Shoots purple, or with dark purple spots. Culm sheaths persistent, leathery, narrowly triangular, 1/3 as long as internodes, glabrous, longitudinal ribs prominent, upper margins ciliolate; auricles and oral setae absent; ligule truncate or inclined-truncate, 1–2 mm; blade reflexed, linear-lanceolate, glabrous, narrow than apex of culm sheath, readily deciduous. Foliage leaves 3–5 per ultimate branch; sheaths 2.5–4.5 cm long, glabrous, purple, margins ciliolate; auricles and oral setae absent; ligules truncate, ca. 1 mm; petiole 1–3 mm long; blades lanceolate, 5–12 × 0.5–1.4 cm, abaxially densely white pubescent, base cuneate, secondary veins 3–4 pairs, transverse veins conspicuous, margins serrate. Inflorescence unknown.
New shoots July to August.
The specific epithet refers to the color of culm sheath and leaf sheath.
Zǐ Qiào Jiàn Zhú (Chinese pronunciation); 紫鞘箭竹 (Chinese name).
Fargesia purpurea is only known from the type locality, bamboo mountain of new village in Zayu county. It grows under the evergreen broadleaved forest at an elevation of 2700–2800 m alt.
Fargesia purpurea D.Z. Li & X.Y. Ye A internodes, showing branches and persistent culm sheath B young culms with culm sheaths C culm bud D branches E node, showing brown setae below node F culm sheath, showing details of blade and ligule G branchlet H leaf sheath I abaxial surface of leaf, showing densely pubescence.
China, Xizang (Tibet), Zayu County, Xiachayu Town, bamboo mountain of new village, 28°32'04"N, 96°59'07"E, 2724 m alt., 24 August 2015, X.Y.Ye & X.He YXY254‐2 (KUN!).
Morphological comparisons between Fargesia purpurea and the related species were provided in Table
Characters | Fargesia purpurea | Fargesia pauciflora | Fargesia brevistipedis |
---|---|---|---|
Culm height | (3)4–5(6) m | 2–4 m | 4–5 m |
Culm diameter | 0.5–1.4 cm | 1–3 cm | 1.2–2 cm |
Internode | 30–46 cm long, longitudinal ribs prominent, densely white powdery, with a ring of 4–5 mm brown setulose; wall 1–4 mm thick | 35–40 cm long, longitudinal ribs prominent, initially densely white powdery, glabrous; wall 2–3 mm thick | 28‐35 (40) cm long, initially white powdery, glabrous; wall 1.5–2(3) mm thick |
Branch complement | 3–7 | 6–10 | many |
Sheath scar | Prominent, glabrous, with persistent remains of sheath base | Prominent, initially densely yellow-brown setose | Prominent, initially yellow-brown setose |
Culm sheath | Persistent, glabrous, upper margins yellow-brown ciliolate initially | Persistent or gradually deciduous, glabrous or sparsely yellow-brown setose, margins brown ciliate | Persistent or gradually deciduous, glabrous or sparsely yellow-brown setose, white powdery, margins brown ciliate |
Culm sheath ligule | Truncate or inclined-truncate, 1–2 mm | Truncate or arcuate, 1–2.5 mm | Truncate or arcuate, 1–1.5 mm |
Culm sheath blade | Reflexed, readily deciduous, | Reflexed, linear-lanceolate, glabrous | Reflexed, linear or linear-triangular, |
Leaf number of the ultimate branch | 3–5 | 2 or 3 | (3)5(6) |
Leaf sheath | Purple, glabrous | Glabrous | Purple or light green, glabrous |
Leaf oral setae | Absent | Absent | 4–8, 5–6 mm long |
Leaf ligule | Truncate, 1 mm tall | Arcuate or truncate, glabrous | 0.5 mm tall |
Petiole | 1–3 mm long | Initially abaxially pubescent | Initially pubescent |
Leaf blade | 5–12 × 0.5–1.4 cm, secondary veins 3–4 pairs, abaxially densely pubescent | 9–14 × 0.7–1.2 cm, secondary veins 2–4 pairs, abaxially pubescent | 6.5–11.5 × 0.5–0.85 cm, secondary veins 3–4 pairs, initially abaxially gray pubescent |
Habitat | Under the evergreen broadleaved forest at the altitude of 2700–2800 m, Zayu, Xizang (Tibet). | Under the Pinus or broadleaved forest, or under shrubs, 2000–3200 m, southwest Sichuan and northeast Yunnan. | Under shrubs at the elevation of about 1250 m, central Sichuan. |
Both Fargesia viridis and F. purpurea have persistent culm sheaths and buds containing several obscure buds, making them belong to the section Fargesia. The shape of culm sheaths is different from these two species. F. viridis is characterized by narrowly rounded culm sheath, with apex nearly as wide as base, which is similar to the species of the series Murielae. F. purpurea is characterized by triangular culm sheaths, shorter than internodes, with apex narrower than base; these features are similar to those species of the series Yunnanenses. Therefore, F. viridis and F. purpurea are assigned to the series Murielae and series Yunnanenses, respectively.
Fargesia is a polyphyletic genus and could be divided into three or four clades based on plastome sequences (
Fargesia viridis (F. sp.2 in Fig.
Fargesia purpurea resembles F. pauciflora and F. brevistipedis by its internode length, prominent sheath scar, culm sheath persistent, auricles and oral setae absent, and leaf blade abaxially pubescent, but differs in terms of the habitat, thinner culm, internode with a ring of 4–5 mm brown setulose, less branch number, glabrous culm sheath and sheath scar.
Mountains of Southwest China are the diversity center for Fargesia species; 80 out of 85 are distributed in this area and 73 of them are endemic. The two new species established here are also distributed in these mountains, indicating that the species diversity of Fargesia in this region may be beyond our knowledge. The species of Fargesia have an island-like distribution and allopatric speciation might have great impact on their diversity (
We thank Xie He of Kunming Institute of Botany, Chinese Academy of Science, and the guide of Zayu county, Xizang (Tibet), for their assistance with field work. The study was funded by the National Natural Science Foundation of China (No. 31800315, 31430011), and the Applied and Fundamental Research Foundation of Yunnan Province (2019FD059).