Potentilla asterotricha (Rosaceae) is a mysterious narrowly local endemic of China from Gansu province

Аннотация

This study provides new data on Potentilla asterotricha, a species endemic to China. The species was described in Gansu province without specific information on locations, collectors, or date of collection. It is not given in “Flora of China”. Additional herbarium materials we discovered in KUN, PE and WUK allowed us to significantly expand the information about this enigmatic taxon. It turned out that its classic habitat is Erlang Mountain in the south of Gansu province in Min County. Based on the presence of stellate hairs in the pubescence, P. asterotricha is assigned here to the section Fasciculato-pilosae. The closest species to it is P. acaulis, from which it differs in the presence of pinnate leaves in the basal rosette. Photos of the leaf blade and pubescence of P. asterotricha under a microscope, as well as a scanned image of its herbarium specimen, are presented. The map shows the distribution of the taxon under study and its putative parent species. The southern border of the P. acaulis range has been identified.

Acta Biologica Sibirica 10: 227–234 (2024) doi: 10.5281/zenodo.10969490

Corresponding author: Alexey Kechaykin (alekseikechaikin@mail.ru)

Academic editor: R. Yakovlev | Received 18 December 2023 | Accepted 5 April 2024 | Published 14 April 2024

http://zoobank.org/4654B080-998C-43BB-B19C-DE8975044EB0

Citation: Kechaykin A, Feng T, Xue TT (2024) Potentilla asterotricha (Rosaceae) is a mysterious narrowly local endemic of China from Gansu province. Acta Biologica Sibirica 10: 227–234. https://doi.org/10.5281/zenodo.10969490

Keywords

China North-Central, endemism, Fasciculato-pilosae, new data, Potentilla

Introduction

The phylogenetically complex Potentilla L. (Dobes and Paule 2010; Persson et al. 2020; Xue et al. 2024) has about 300 species in the narrow sense (Kechaykin et al. 2021). In “Flora of China” this genus is accepted in a broad sense (including Argentina Hill, Dasiphora Raf., Drymocallis Fourr. ex Rydb. and Sibbaldianthe Juz.) and is represented by 86 species (Li et al. 2003). However, in less than 10 years, the number of Potentilla s. l. in China has almost doubled. Thus, the famous researcher of the tribe Potentilleae Sweet J. Soják lists 161 species, of which 29 are endemic (Soják 2012). Among the endemic species he identified, 20 are native to Sichuan and Yunnan, confirming the conclusions of Huang et al. (2011). The data presented above indicate that the territory of China is one of the centers of speciation and species diversity of Potentilleae. In this regard, the study of Potentilla endemism in China remains relevant.

Endemic plants are a specific and integral part of any flora, and multilateral studies of these species play an important role in the analysis of floras (Zhang et al. 2022). Endemics that arose in conditions of isolation and live in small areas are carriers of a unique gene pool and thus serve as primary objects of protection (Huang et al. 2016). Meanwhile, in the flora of China, several Potentilla endemics are known only based on original descriptions, and their herbarium materials are represented only by type specimens. We devoted this study to one of these species called P. asterotricha Soják, a narrowly local endemic from Gansu province, missed in “Flora of China”, and about which there was no additional information for more than 20 years after its original description.

Materials and methods

The material for the analysis was samples of P. asterotricha stored in the Herbariums KUN, PE, PR and WUK. Acronyms are adopted according to the “Index Herbariorum” (Thiers 2023). Morphology of individual parts was studied, and the corresponding photographs were taken using a Carl Zeiss Discovery V8 stereoscopic microscope. We also used the ArcGIS 10.6 to visualized the geographic distribution of P. asterotricha and its related species (P. potaninii and P. acaulis). The occurrence records of these three species were accessed form the Chinese Virtual Herbarium (http://www.cvh.ac.cn/) and the Global Biodiversity Information Facility (https://www.gbif.org/). Then, we removed coordinates that outside the species’ native range recorded in Plants of the World Online (https://powo.science.kew.org/). The filtered distribution data are listed in Suppl. material 1: Table S1.

Result

Taxonomic treatment

Potentilla asterotricha Soják, Preslia 64(3): 214, fig. 2/32, 1993.

Type: Potentilla asterotricha sp. n. Habitat: China, prov. Gansu. Legit: sine coll. (holotype: PR616286!).

According to protologue: “Typus: China, Gansu – sine collectore et loco propiore, PR” (Soják, 1992, p. 214).

The reason why the type of material of P. asterotricha without detailed label data ended up in the PR Herbarium is unknown. However, J. Soják points out that another specimen of P. asterotricha, identified as P. acaulis, is kept in Beijing and has a full herbarium label (Soják 1992: 214). Why the author did not quote this sample is also unknown. In the PE Herbarium we were able to find one herbarium specimen identified by Yü and Li in 1975 as P. acaulis. Specimens of this plant collected in Gansu province were found to be identical in morphology to P. asterotricha from PR. The sample label data is written in Chinese. Perhaps it was this Beijing sample that J. Soják had in mind. According to the International Code of Nomenclature of Algae, Fungi and Plants (Shenzhen Code), this sample should be considered as the original material (Turland et al. 2018: Art. 9.4). Below is a full quote from the sample label translated into English, as well as the barcode number and a link to access the scanned image.

Original specimen: Gansu, Min County, Erlang Mountain. Habitat: mountain slope and bushwood, alt. 2400 m; herb, flower: yellow; collected date: 1957.05.26; collector: Tao River Expedition (a group of people who investigate the plant near Tao river, a tributary of the upper reaches of the Yellow River in China) (PE00828054!, https://www.cvh.ac.cn/spms/detail.php?id=f0ef743a).

In addition, we were able to find herbarium specimens with identical labels in KUN (KUN609126!) (Fig. 1) and WUK (WUK0091483). Based on new materials studied, we supplement the morphological description of P. asterotricha and present it below.

Low-growing perennial plant with a well-branched caudex (with numerous particulates). Generative shoots are shortened, 4–7 cm long, with 1–3 reduced leaves. Basal leaves are 1.5–4 cm long, mixed with trifoliate and pinnate. Pinnate leaf blades have two pairs of lateral leaflets (Fig. 2A). Terminal leaflets of basal leaves 0.7–1.5 cm long with 2–5 teeth on each side. Petioles and stems are covered with long (0.5–1 mm) bristly straight and curved, as well as short (0.1–0.3 mm) soft straight and curved hairs. All leaves are greyish-greenish on top, densely covered with appressed simple hairs mixed with stellate ones; below are grayish-whitish with dense felt pubescence (stellate hairs are difficult to distinguish). The inflorescence is loose with 2-4 flowers, about 1 cm in diameter. Calyx densely covered with simple and stellate hairs. The central ray of stellate hairs is much longer (about 0.34 mm) than the other rays (Fig. 2B). Petals are about 5 mm long and longer than the sepals. Anthers 0.5–0.7 mm long. Styles is subterminal, 1.1–1.2 mm long, slightly widened at the base. Achenes are unknown.

Figure 1.Herbarium specimen of P. asterotricha (KUN609126).

Potentilla asterotricha Soják was described as closely related to P. acaulis L. from a collection in Gansu province, China, but differing from it in having pinnate leaf blades with two pairs of lateral leaflets (Fig. 2A). Stellate hairs of P. asterotricha are clearly visible on the calyx and along the edges of leaflets (Fig. 2B). According to J. Soják, this plant is of hybridogenic origin, with one of its parents being certainly P. acaulis, and the other, perhaps, P. potaninii Th. Wolf (Soják 1992). Both putative parent species are widely distributed in China and are found in Gansu province (Li et al. 2003) (Fig. 3). Unfortunately, the age of the herbarium material (more than 65 years) does not allow us to conduct a high-quality molecular study to confirm or refute the hypothesis about the hybridogenic nature of P. asterotricha. However, based on the presence of stellate hairs, we can assign it to the section Fasciculato-pilosae Kamelin. This section includes about 10 taxa, distributed only in Eurasia and having pubescence of stellate hairs (e.g., P. acaulis, P. boreo-caucasica Kechaykin, P. cinerea Chaix ex Vill., P. incana G. Gaertn., B. Mey. & Scherb.) (Kamelin 2001).

Distribution and ecology

After the initial description, P. asterotricha was, for some reason, not listed for the Flora of China (Soják 2007; Li et al. 2003; Zhang and Li 2007), but was only listed only in the key for definition in “Notes on Potentilla XXVIII” (Soják 2012: 32). The type specimen kept in the PR gave no indication of its exact geography. Thus, for the first time, we present here the specific location of this rare national endemic of China.

The species was found in China North-Central in the south of Gansu province in Min County, where its classic habitat is Erlang Mountain in the Tao River basin. It turned out that the southern border of the range of P. acaulis also lies within this territory (Fig. 3). Specimens of P. asterotricha were collected among mountain slopes and bushes at an altitude of 2400 m a.s.l. (according to herbarium labels). This is consistent with the ecology and altitudinal zonation of P. acaulis and P. potaninii according to Li et al. (2003). Apart from four herbarium specimens from KUN, PE, PR and WUK, no collections of P. asterotricha have been found to date.

Figure 2.Pinnate basal leaf (A) and stellate hair with marked central ray (B) of P. asterotricha.

Figure 3.Distribution map of P. acaulis, P. asterotricha and P. potaninii. The black line is the province boundary of China.

Acknowledgements

The authors thank the curators of the Herbariums PE, PR, KUN and WUH for their assistance in finding and studying specimens of P. asterotricha.

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Supplementary material 1

Table S1. The distribution data of Potentilla acaulis , Potentilla potaninii and Po tentilla asterotricha

Authors: Alexey Kechaykin, Tao Feng, Tian-Tian Xue

Data type: table

Copyright notice: This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.

Link: http://journal.asu.ru/biol/article/view/15043/12769