Research Article |
Corresponding author: Yu-Bing Wang ( tomswfc1977@163.com ) Academic editor: Yasen Mutafchiev
© 2019 Yu-Bing Wang, Xing-Jun Xiong.
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:
Wang Y-B, Xiong X-J (2019) Sedum ichangensis, a new species of Crassulaceae from Hubei, China. PhytoKeys 132: 91-98. https://doi.org/10.3897/phytokeys.132.35428
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Sedum ichangensis sp. nov., from Yichang, Hubei province, central China, is described and illustrated. The new species is similar to S. elatinoides and S. rosthornianum in its leaf and carpel morphology and differs in its creeping stems and solitary flowers. The conservation status of S. ichangensis was assessed as Endangered according to the IUCN Red List criteria.
Crassulaceae, Flora of China, Flora of Hubei, new species, Sedum sect. Filipes
Sedum
According to the recent taxonomic treatment of
An unknown Sedum species, belonging to the sect. Filipes, was discovered in Hubei Province, Central China. The species is described as new to science in this study.
Three scattered populations of an unknown Sedum species were discovered in Yichang city of Hubei Province, Central China in 2014. These populations were continuously observed over 2 years. Fresh specimens collected from these populations were morphologically studied and illustrated. The distribution map was constructed with Arcgis 10.2, using data provided on the specimen labels.
Specimens of the morphologically similar species Sedum elatinoides
Sedum ichangensis has papillate carpels and appears to be morphologically similar to S. elatinoides and S. rosthornianum. It can be distinguished from S. elatinoides by its perennial habit (vs. annual) and solitary flower (vs. flowers in cymes) and from S. rosthornianum in its entire leaf margins (vs. leaf margins dentate), its branched stems (vs. stems simple) and its solitary flowers (vs. flowers in paniculiform cymes). (Table
Item | Sedum ichangensis | Sedum elatinoides | Sedum rosthornianum |
Habit | perennial | annual | perennial |
Stem | prostrate | erect | erect |
Phyllotaxis | 4–6-verticillate | 3–6-verticillate | opposite or 3- or 4-verticillate |
Leaf blade | narrowly ellipsoid, entire | narrowly oblanceolate, entire | rhombic-oblong, dentate |
Inflorescence | solitary flower | paniculiform or corymbiform cyme | paniculiform cyme |
Petal | white, pinkish toward the apex | white | white |
CHINA: Hubei Province, Yichang city, Changyang County, Longzhouping Town, on rocks, alt. 130 m. 30°28'N, 111°11'E, 19 Jul 2017, ycmy032 (holotype, CTGU!; isotypes HIB!, and PE!).
Perennial herbs. Roots fibrous. Stems procumbent, divaricately branched, 1–2 mm in diameter, up to 35 cm long, with scattered reddish dots. Leaves 4–6-verticillate, entire, sessile, narrowly ellipsoid, 5–12 × 1.5–2.5 mm, base attenuate, apex acute. Flowers 5-merous, solitary in the axils of upper leaves, 5–8 mm in diameter. Pedicel 1.5–2.5 cm long. Sepals 5, lanceolate, 1.5–2 mm long, apex acute. Petals 5, white, pinkish towards the apex, lanceolate, 4–5 × 1–2 mm, apex acute. Stamens 10, in 2 whorls, slightly shorter than the petals, antesepalous ones ca. 4 mm long, antepetalous ones ca. 3 mm long, inserted ca. 1 mm above the petal base, filaments white, 1.6–2.4 mm long, anthers ca. 0.4 mm long, reddish. Nectar scales spatulate, ca. 0.4 mm long. Carpels 5, white, suberect, adaxially minutely papillate, broadly ovoid, ca. 2 mm long, base united for ca. 0.2 mm, styles ca. 1.5 mm long. Follicles divergent, 0.8–1.1 mm long, with scattered reddish dots, seeds numerous, brown, ca. 0.5–1 mm long, papillate.
Flowering from early May to July, fruiting from August to October.
Sedum ichangensis is known from Longzhouping town of Changyang County, Gufu town of Xingshan County and Muyang River of Yiling County in Yichang City of western Hubei Province, central China (Fig.
Yi-chang-jing-tian (宜昌景天).
The specific epithet of this new species is dedicated to the Yichang city.
Sedum ichangensis belongs to Sedum sect. Filipes on account of its carpels adaxially not gibbous, its spurless leaf base and its white flowers (
CHINA. Hubei Province: Xingshan County, Gufu town, 200 m alt., 31°20'N, 110°45'E, 15 May 2017, YB Wang ycmy022 (CTGU), same loc. XJ Xiong XXJ024 (CTGU); Yiling County, Muyang River, 280 m alt., 30°44'N, 111°02'E, 3 August 2017, YB Wang ycmy139 (CTGU).
Based on field investigations, S. ichangensis occurs only in three scattered areas. The total area of occupancy is less than 500 km2; each population possesses no more than 300 mature individuals. It prefers habitats on rocks along roads. Human activities are impairing its populations severely. The type population, which grew close to a road, was seriously impacted in its survival due to herbicide spraying in 2018. Based on currently available information, the conservation status of this species is categorised as Endangered [EN] following the IUCN Categories and Criteria (
1 | Plants perennial, fasciculate; stamens in 1 series | S. correptum |
– | Plants annual or biennial, rarely perennial, solitary or tufted; stamens in 2 series | 2 |
2 | Plants glandular hairy | 3 |
– | Plants glabrous. | 4 |
3 | Plants annual; stems soft; leaves 2–4 × 1.4–2.5 cm | S. drymarioides |
– | Plants biennial; stems ± woody at base; leaves 0.7–1.5 × 0.7–0.9 cm | S. stellariifolium |
4 | Carpels minutely papillate | 5 |
– | Carpels smooth | 7 |
5 | Stems simple, erect; leaf margin dentate | S. rosthornianum |
– | Stems many branched, decumbent; leaf margin entire | 6 |
6 | Plants annual; stems erect, flowers in cymes | S. elatinoides |
– | Plants perennial, stems creeping, flowers solitary | S. ichangensis |
7 | Carpels 3 | S. bonnieri |
– | Carpels 5 | 8 |
8 | Petals reddish-purple; flowering stems branched, ca. 20 cm | S. filipes |
– | Petals white; flowering stems simple, ca. 10 cm | S. majus |
We would like to thank Associate Professor Qiao Li for her excellent illustrations of S. ichangensis. Thanks are also due to the reviewers for their useful suggestions. This study was supported by the Special funds for science and technology innovation of Hubei (grant no. 2018ACA132).