Research Article |
Corresponding author: Qiang Fan ( fanqiang@mail.sysu.edu.cn ) Academic editor: Hugo de Boer
© 2020 Su-Fang Chen, Kai-Kai Meng, Xi-Bing Guo, Wan-Yi Zhao, Wen-Bo Liao, Qiang Fan.
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:
Chen S-F, Meng K-K, Guo X-B, Zhao W-Y, Liao W-B, Fan Q (2020) A new species of Eriobotrya (Rosaceae) from Yunnan Province, China. PhytoKeys 146: 61-69. https://doi.org/10.3897/phytokeys.146.50728
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Eriobotrya laoshanica, a new species of Rosaceae from Yunnan, China, is described and illustrated. The new species is easily distinguished from the most similar species E. malipoensis K. C. Kuan by its longer petioles (2–5 vs. 0.5–1 cm); indumentum on the lower leaf surfaces (densely tomentose vs. glabrous); much fewer flowers (15- to 30-flowered vs. 50- to 100-flowered) on the panicle; larger flowers (2.5–3 vs. 1.5–2 cm in diameter); and non-angulated (vs. angulated) young fruits.
chloroplast genome sequences, morphology, phylogeny, subtribe Malinae
The genus Eriobotrya Lindley, a small genus of subtribe Malinae (tribe Maleae, subfamily Amygdaloideae, Rosaceae) consisting of approximately 30 species, is distributed in Himalaya, eastern Asia and western Malesia (
There are about 16 Eriobotrya species (five endemic) recorded in China (
Morphological observations of the putative new species and its close relatives were carried out based on living plants in the field as well as dried specimens. All morphological characters were measured using a stereomicroscope with ocular micrometer (Leica S8APO, Leica Microsystems Inc., Germany). The voucher specimens were deposited in the herbarium of Sun Yat-sen University (
Leaf samples for the putative new species were collected and stored in silica gel. The total DNA was extracted with the TIANamp Genomic DNA Kit [TIANGEN Biotech (Beijing) CO. Ltd] according to the protocol procedure, and then sent to Novogene Bioinformatics Technology (Beijing, China) Co. Ltd for quality inspection and low-coverage genome sequencing using Illumina 2000 platform following the standard Illumina sequencing procedure. Approximately 6 GB cleaned raw data was produced and assembled into circled chloroplast genomes with the perl script NOVOPlasty2.7.2 (
The alignment length of these twenty-five chloroplast genomes was 166,363bp in total, with the statistics of 1,307 parsimony-informative sites. No variable sites were detected between the two accessions of the new species but 139 variable sites were detected between the new species and E. malipoensis. This low diversity within the species was also observed in E. japonica (KT633951 was also identical to NC_034639, KY085905 identical to MN577877).The best-fit nucleotide substitution model was detected as TVM+F+R2 based on Bayesian Information Criterion (BIC). The ML phylogenetic tree (Fig.
China. Yunnan Province, Malipo County, Mount Laoshan, in thin forests on the slopes of limestone hills, 22°59.08'N, 104°50.48'E, 1160 m a.s.l., 14 October 2019, Q. Fan 17570 (holotype:
Eriobotrya laoshanica sp. nov. A fruiting branch B inflorescence C flower, front view D petal, adaxial view E flower without corolla showing hypanthium and calyx lobes F fruit G fruit, in longitudinal section H fruit, in transverse section. A and F–H from Q. Fan 13900 B–E from Q. Fan 17570. Drawn by Yun-Xiao Liu.
This species is similar to E. malipoensis and E. serrata, but differs from them in its leaf shape, indumentum on the lower leaf surfaces, longer petioles, much fewer flowers on the panicle, larger flowers, and other traits.
Evergreen small tree, 4–10 m tall, much branched; stems 8–25 cm in diameter; branchlets grey-white, terete, glabrous, 6–10 mm in diameter. Leaves spirally inserted on branches and often crowded at tips of branchlets; petioles 2–5 cm long, glabrous; stipules elliptic or ovate-lanceolate, 1–3 × 0.5–1 cm, glabrous, caducous; leaf blades oblong or broad elliptic, 20–40 × 7–12 cm, thickly coriaceous, glabrous, midrib elevated on both surfaces, secondary veins 21–30 pairs, arching slightly and often dichotomous before reaching the margin, elevated on both surfaces margin serrate, apex acute or cuspidate, base cuneate, gradually tapering to the petiole. Inflorescence in terminal panicles, 15- to 30-flowered, 8–15 cm long, 6–10 cm in diameter, with 6–10 lateral racemes, the lowermost laterals in the axils of reduced leaves (often almost entirely consisting of the stipules only), upper ones in axils of bracts, lateral racemes sometimes branched in the lower part of the inflorescence; peduncle and pedicels densely yellow-brown tomentose; bracts ovate-triangular, 1–1.5 cm long, abaxially tomentose, adaxially glabrous or sparsely pubescent; bracteoles subulate or triangular, 3–8 mm long, abaxially densely tomentose, adaxially pubescent. Flowers 2.5–3 cm in diameter. Hypanthium obconical, 4–6 × 5–7 mm, abaxially densely yellow-brown tomentose, 5-lobed, the calyx lobes ovate, 3–5 × 2–4 mm, abaxially densely tomentose, adaxially glabrous; petals white, obovate or rotund, 6–9 × 5–10 mm, shortly clawed, glabrous, margin crisped or irregularly crenulate, apex retuse; stamens 20; flaments 3–6 mm long, glabrous; anthers 1–2 mm long; ovary semi-inferior, the free apex densely villous, ovoid, 2–3 mm across, 3–5-loculed, with 2 ovules per locule; styles 3–5, densely villous, 5–7 mm long, connate at base or fused from base to middle; ovules ovoid or ellipsoid, c. 1 mm across. Pome yellow at maturity, subglobose, 2.5–3.5 cm in diameter, glabrescent, crowned by the persistent calyx lobes forming an apical beak; pericarpium fleshy, ca. 3 mm thick. Seeds (1-) 2 per fruit.
Flowering from September to October, fruiting from November to December.
The specifc epithet refers to Laoshan Mountain, the locality of the type collection.
Eriobotrya laoshanica is currently known only from two localities in Laoshan Natural Reserve, Malipo County, southeastern Yunnan, China. Here, the species is distributed in thin forests on the slopes of limestone hills at altitudes of 1100–1358 m a.s.l. The common associated tree species include Aucuba chinensis, Caryodaphnopsis tonkinensis, Ficus semicordata, Firmiana sp., Garcinia paucinervis, Machilus sp. and Syzygium claviflorum.
Only two populations were found with no more than 50 mature individuals in a total area of about 5 km2. It’s about 6.5 km away between the two populations. The wood of this species is very suitable for firewood. During the expedition in 2019, we found that at least two big trees about 15 cm in diameter were felled by the local villagers. Thus the species could be considered as CR (Critically Endangered) status according to IUCN Red List criteria (B2ab(v);
The closest relative of Eriobotrya laoshanica on morphological grounds could be E. malipoensis Kuan, which usually coexists with the new species. They shared several characteristics, e.g., the long thick-coriaceous leaves that are up to 40 cm long; styles 3–5; and the subglobose fruits. The new species can be distinguished from E. malipoensis, however, by its longer petioles (2–5 vs. 0.5–1 cm); indumentum on the lower leaf surfaces (densely tomentose vs. glabrous); much fewer flowers (15- to 30-flowered vs. 50- to 100-flowered) on the panicle; larger flowers (2.5–3 vs. 1.5–2 cm in diameter); and non-angulated (vs. angulated) young fruits. E. laoshanica also has some resemblance to E. serrata Vidal but differs in its thicker leaves; leaf shape (oblong to broad elliptic vs. obovate to oblanceolate); more lateral veins (21–30 vs. 10–16 pairs); and larger fruits (2.5–3.5 vs. 1.5–1.8 cm in diameter) (Table
To distinguish these species of Eriobotrya flowering in autumn and winter (from September to February) in China, an identification key is provided (based on
Morphological comparisons amongst Eriobotrya laoshanica, E. malipoensis and E. serrata. A–C leaves of E. serrata (A), E. malipoensis (B) and E. laoshanica (C) D–F abaxial leaf surface of E. serrata (D), E. malipoensis (E) and E. laoshanica (F) G, H flowers of E. malipoensis (G) and E. laoshanica (H). Photos taken by Qiang Fan.
Morphological comparisons amongst Eriobotrya laoshanica, E. malipoensis and E. serrata.
Characters | E. laoshanica | E. malipoensis | E. serrata |
---|---|---|---|
Leaf shape and size | oblong or broad elliptic, 20–40 × 7–12 cm | oblong or oblong-obovate, 30–40 × 10–15 cm | obovate or oblanceolate, 9–23 × 3.5–13 cm |
Texture of leaves | thickly coriaceous | thickly coriaceous | thinly coriaceous |
Indumentum on the lower leaf surfaces | glabrous | densely rusty tomentose | tomentose when young, glabrescent |
Petiole length | 2–5 cm | 0.5–1 cm | 1.5–3 cm |
Lateral veins | 21–30 pairs | 20–25 pairs | 10–16 pairs |
Inflorescences | with reduced leaves, 15- to 30-flowered | without reduced leaves, 50- to 100-flowered | without reduced leaves, 30- to 60-flowered |
Flower size (diameter) | 2.5–3 cm | 1.5–2 cm | 1–2 cm |
Fruit shape and size (diameter) | subglobose, 2.5–3.5 cm | pyriform, 2–3.5 cm | ovoid or pyriform, 1.5–1.8 cm |
China. Yunnan: Malipo, Laoshan natural reserve, 22°58.66'N, 104°50.80'E, 1135 m a.s.l., 16 September 2015 (young fl.), Q. Fan 13700 (
1 | Leaves abaxially glabrous or glabrescent | 2 |
– | Leaves abaxially rusty or gray persistent tomentose | 3 |
2 | Leaves abaxially glabrous | E. laoshanica |
– | Leaves abaxilly brownish yellow tomentose when young, glabrescent | E. serrata |
3 | Leaves abaxially rusty tomentose; leaf blade 30–40 cm long; lateral veins 22–25 pairs | E. malipoensis |
– | Leaves abaxially gray tomentose; leaf blade 7–30 cm long; lateral veins 9–16 pairs | 4 |
4 | Leaf blade adaxially rugose; styles 5 | E. japonica |
– | Leaf blade adaxially not rugose; styles 2–4, rarely 5 | 5 |
5 | Stipule subulate; inflorescences 8–12 cm long; pome 1.5–3 cm in diam | E. × daduheensis |
– | Stipule ovate; inflorescences 6–10 cm long; pome 0.6–1 cm in diam | E. prinoides |
We are deeply grateful to Mrs Yun-Xiao Liu for her excellent illustration in the manuscript. This study was supported by the National Natural Science Foundation of China (31670189, 31800175), Natural Science Foundation of Guangdong Province (2016A030313326, 2017A030310421, 2018A0303130109), and the project of the Fourth Survey of Chinese Traditional Medicine Resources (2019-302-001; 2019-303-001).