Astragalus arbuscula (Fabaceae): A new record for Mongolian flora

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Korean J. Pl. Taxon. 2024;54(3):212-216

Publication date (electronic) : 2024 September 30

doi : https://doi.org/10.11110/kjpt.2024.54.3.212

Shukherdorj BAASANMUNKH, Dariganga MUNKHTULGA¹, Batlai OYUNTSETSEG¹, Altangerel UNDRUUL¹, Zagarjav TSEGMED, Alexey A. KECHAYKIN², Hyeok Jae CHOI

Department of Biology and Chemistry, Changwon National University, Changwon 51140, Korea

¹Department of Biology, School of Arts and Science, National University of Mongolia, Ulaanbaatar 14201, Mongolia

²South Siberian Botanical Garden, Altai State University, Lenina 61, Barnaul 656049, Russia

Corresponding author: Hyeok Jae CHOI, E-mail: hjchoi1975@changwon.ac.kr

Received 2024 May 16; Revised 2024 August 24; Accepted 2024 September 9.

Abstract

INTRODUCTION

The genus Astragalus L. encompasses as considerable array of species within the Fabaceae family, comprising over 3,000 taxa globally (Podlech and Zarre, 2013; Plants of the World Online, 2024). This genus exhibits widespread distribution across Asian countries such as China, Iran, Mongolia, and Uzbekistan (Maassoumi and Ashouri, 2022). In Mongolia specifically, Astragalus is one of the largest genera, with 127 taxa predominantly found in the western and southern parts of the country (Ulziykhutag, 2004; Baasanmunkh et al., 2022). Recently, we found two new records of Astragalus including Astragalus testiculatus Pall. and A. teskhemicus Sytin & Shaulo for the Mongolian flora (Baasanmunkh et al., 2024). Notably, among these taxa, 15 are endemic, while 23 are considered subendemic (Baasanmunkh et al., 2021, 2022). In the past, the taxonomic classification of Astragalus was extensively revised, considering its morphology and distribution in Mongolia (Ulziykhutag, 2003, 2004). Nevertheless, new species and records of Astragalus continue to be documented in the country (Pyak and Pyak, 2019; Baasanmunkh et al., 2024).

Astragalus arbuscula Pall. is shrub or subshrub species and occurs in China, Kazakhstan and Russia (Yakovlev 1996; Podlech and Zarre, 2013; Plants of the World Online, 2024). Taxonomic classification of this species belongs to section Dissitiflori and subgenus Cercidothrix (Podlech and Zarre, 2013). The seed testa structure of this species reticulate with oblong-elliptical shape (Shemetova et al., 2018).

Here, we reported that A. arbuscula is a novel record for the Mongolian flora based on our field expeditions in western Mongolia.

MATERIALS AND METHODS

In 2016, we conducted field surveys in the western part of Mongolia, specifically focusing on the Khovd province. During the field surveys, we collected unlisted species of Astragalus from Yarant, Khovd province. Additionally, we examined herbarium specimens from ALTB, LE, MW, and UBU (Thiers, 2024). Detailed photographs of Astragalus arbuscula were taken during the field surveys. ArcGIS version 10.8 was used to create the map.

RESULTS AND DISCUSSION

Until now, A. arbuscula has been documented in China, Kazakhstan, and Russia (Podlech and Zarre, 2013). However, this species could potentially occur in Mongolia due to its general distribution being close to the western part of the country (Podlech and Zarre, 2013). However, this species has never been mentioned in previous publications in Mongolia (Ulziykhutag, 2003; Podlech and Zarre, 2013; Baasanmunkh et al., 2022). In this study, we newly discovered it in 2016 in the western part of Mongolia. Additionally, we found a single herbarium specimen of this species, collected in 1999 without any associated publications, which was stored at the South-Siberian Botanical Garden (ALTB1100012005) and is also available in GBIF (https://www.gbif.org/occurrence/2443043832). Both the herbarium specimen and our collection of A. arbuscula were found in the same location in the Khovd province, Mongolia.

In Mongolia, A. majevskianus Krylov, A. suffruticosus Pall., A. syriacus L., and A. xanthotrichos Ldb., are shrub or subshrub species (Ulziykhutag, 2003; Podlech and Zarre, 2013). In addition, A. arbuscula, our newly found species, is one of the shrub species but distinguished from other shrub species by its several morphological characters including the racemes many-flowered, calyx tubular, unchanged until fruiting time, ruptured by peduncle, legumes narrowly-linear, with appressed hairs, not bladderlike inflated, all stipules free from each other, leaflets (2) 3–4 pairs. In addition, the general morphology of this species is similar to A. gontscharovii Vassilcz., but it can be differentiated by its bracts 1–2 mm, black ciliate, calyx covered with strongly asymmetrically bifurcate, standard without tongue-like narrowed tip (Podlech and Zarre, 2013).

Astragalus arbuscula Pall., Sp. Astragal. 19, n. 24, t. 17 1800. Tragacantha arbuscula (Pall.) Kuntze, Revis. Gen. 2: 943, 1891.––TYPE: Kazakhstan, in australibus deserti Kirgiso-Songarici circa Chasyl-tasch, inter Irtim fluv. et lacum Balchasch, Sievers (LIV, the left plant) (lectotype, BM photo!) (Fig. 1).

Fig. 1.

Astragalus arbuscula in Mongolia. A. General habitat. B. Raceme. C. Flower. D. Leave. E. Legumes.

Plants subshrubs, branched, 30–110 cm tall, covered with mostly medifixed, appressed white hairs. Stems several, branched near the base, the older parts (10–)30–60 cm, ligneous, covered with chestnut-brown, longitudinal splitting bark. Stipules greenish, 2–4 mm, triangular-ovate to narrowly ovate-acuminate or narrowly triangular. Leaves 2–5 cm, subsessile; rachis 1–2 cm, rather densely hairy. Leaflets in 2–4 pairs, linear, 6–30 × 1–3 mm, rarely narrowly elliptic and up to 5 mm wide, acute, on upper side loosely, on underside more densely covered with white hairs. Peduncles 5–10 cm, densely hairy like the stem. Inflorescence raceme, ovoid, 2–4 cm, densely 6–18-flowered; peduncle 7–10 cm, densely hairy; bracts 1–3 mm, mostly black ciliate. Calyx 7–10mm, sparsely to densely covered with strongly asymmetrically bifurcate, flexuous, ascending, white hairs up to 1 mm and with distinctly shorter, subappressed, black hairs 0.1–0.3 mm; teeth 1.5–2 mm. Petals purple. Standard rhombic, 15–19 × ca. 6 mm, apex retuse; wings 14–17 mm; keel 11–14 mm. Legumes sessile, spreading or rarely nodding, straight, 20–30 mm, 1–2 mm thick, apex shortly acuminate; valves densely covered with symmetrically or asymmetrically bifurcate, appressed, black hairs and with distinctly asymmetrically bifurcate, appressed to slightly ascending, white hairs 0.5–0.7 mm, rarely only with white hairs.

Distribution. This species is distributed in China (Xinjiang), Kazakhtan (Alma-Ata, Dzezkazgan, Semipalatinsk, Taldy-Kurgan, Tselinograd, Vistochno-Kazakhstanskay), and Russia in Asia (Altai, Gorno-Altaisk) (Podlech and Zarre, 2013; Plants of the World Online, 2024). In Mongolia, this species occurs in the Yarant zastav, Bulgan soum, Khovd province (Figs. 2, 3). The general distribution map was based on previous studies of A. arbuscula (Gontscharov and Popov, 1946; Vinogradova, 1981; Ulziykhutag, 2004). During the field surveys, we found over 50 shrubby individuals in this area.

Fig. 2.

Voucher specimen of Astragalus arbuscula in ALTB.

Fig. 3.

General distribution and the new record in Mongolia for Astragalus arbuscula.

Habitats. This species grows in rocky and stony areas of desert steppe areas.

Specimens examined: MONGOLIA. Dzungarian Gobi region: Khovd province, Bulgan soum, valley of the Bulgan river, 41 km west of the Tayteshkent village, 46°09’00.0”N, 91°00’00.0”E, 1,800 m, a.s.l., 19 Jul 1999, V.S. Smirnov (ALTB1100012005); same locality, 46°08’33.72”N, 91°0’8.8092”E, 1,100 m, a.s.l., 30 May 2016, B. Oyuntsetseg (UBU).

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