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Astragalus L.

The genus contains 38 monotypic sections in the Old World and 24 monotypic sections in the New World. There are also several local and regional endemites sections in different countries of the world. Majority of the sections contain 10 to 60 species and only a few sections consist of  70 to 120 species. Only the sect. Caprini known as the biggest section with about 300 species is widely distributed throughout the old world from south to north hemisphere, in temperate climate to cold area, lowland to high altitude and subnival to nival zone. As the exception Australia and New Zeeland, the genus is widely distributed throughout the world.

From Linnaeus era (1753) till 1794 approximately 84 species (37 spp. by Linnaeus) were described, from 1795 to 1876 about 790 more species were added on previous number, from 1882 to 1915 around 236 species, from 1916 to 1955 about 328 species, and surprisingly from 1956 to 2018 unimaginable species number, about 1175 new taxa( subspecies / varieties) were added in the genus Astragalus. There are actually 2674 accepted species/subspecies / varieties names into 148 sections are recognized from different parts of the Old World countries. For the New World from eighteen century (Hooker, 1831, A. Gray, 1864; Jones, 1923; Rydberg, 1929; Barneby, 1964; and Gomez-Sosa, 1979-1986), about 636 species/varieties into 91 sections for the N America and 107 species without sectional classification for S. America were validated. Now Astragalus with 3367 taxa ( including 213 varieties in New World and 154 subspecies in Old World) is the pioneer within 57 biggest genera of flowering plants in the world (Frodin, 2004).

The genus with very divers in taxonomic characters, 65 different genera described in the genus, but later, part of these genera reduced to section level and a great number of generic names reduced to synonyms of several sections. According the new treatment several sections reduced to synonyms but in few cases there are disagreement within Russian taxonomists the synonymy of some sections.

The genus contains 38 monotypic sections in the Old World and 24 monotypic sections in the New World. There are also several local and regional endemites sections in different countries of the world. Majority of the sections contain 10 to 60 species and only a few sections consist of  70 to 120 species. Only the sect. Caprini known as the biggest section with about 300 species is widely distributed throughout the old world from south to north hemisphere, in temperate climate to cold area, lowland to high altitude and subnival to nival zone. As the exception Australia and New Zeeland, the genus is widely distributed throughout the world. Surprisingly, a few sections (Hypoglottidei, Uliginosi, Onobrychoidei and …) and about 10 species (A. alpinus, A. onobrychis, and …) which are usually growing in wetland or meadows are common within Old and New world. Few numbers of annual species were produced in N America and probably in S Africa.

Morphologically, the species of the genus are in the form of annuals, perennials, herbaceous and fruticose (shrub lets). In SW Asia, Middle Asia and in high altitudes of Europe the woody species create the small to big continuous or discontinuous permanent association with one or more Astragali species and in some parts, mixed with other sociable genera like: Acantholimon spp., Arthemisia spp. Onobrychis spp. and Acanthophyllum spp., which create the association (cushion formation). All other data excluded from different floras (Gontscharov 1965, Davis 1970, Podlech 1999; Podlech et al. 2001, 2010, 2012; Maassoumi 2003, 2016, 2018), Chauhdary, 2018, Podlech & Xu, 2010, Ali, 1980); Check lists (Lock 1991; Yakovlev et al. 1996; Maassoumi 1998, 2018; Kumar et al. 2003; Breckle et al., 2013; Khassanov, 2018) as well as the recent monumental taxonomic revision of the genus in the Old World (Podlech and Zarre, 2013).

More additional data were extracted from herbarium materials of the biggest national herbaria and 20 different provincial herbaria of Iran and also from the Floras and catalogues of some other herbaria of the world. With these data a database in Excel software created with more than 55000 records. These data analyzed with the quantitative inventory method and ArcGIS software.

Based on this huge database (Old World), number of observations were classified in six different major groups:

Group 1: 550 spp. only with one observation belonging to very rare species group.

Group 2: 585 spp. with 2-4 observations belonging to rare species group.

Group 3: 480 spp. with 5-10 observations belonging to abundant species group.

Group 4: 365 spp. with 11-20 observations belonging to frequent species group.

Group 5: 423 spp. with 21-99 observations belonging to widespread species group.

Also, the elevation distribution of samples, is given in below.

Categories/Elevation Frequent Percentage
< 500 m 775 3.95
500-1000 m 1601 8.16
1000-1500 m 3499 17.83
1500-2000 m 5383 27.43
2000-2500 m 4158 21.19
2500-3000 m 1898 9.65
3000-3500 m 1076 5.48
3500-4000 m 653 3.33
4000-4500 m 356 1.81
4500-5000 m 165 0.84
5000-5500 m 54 0.28
> 5000 7 0.04
Sum 19621 100

Based on Phylogentical findings (Kazempour et al, 2003, 2005; Wojciechowski, M.F., et al.,2004; Maassoumi et al., 2016), the major primitive groups of the genus Astragalus with herbaceous habits and large flowers with wide keels (Colutea types) are usually concentrated in SW, SE and Middle Asia, however, an explosive rapid radiation is prolonged to Indo-Himalaya and Northern Africa.

The species of this genus distributed unequally from low to high altitudes with different number of endemism in Asia, Europe, Africa and America. In Europe with 134 spp. (59 endemics), SW Asia with 1511 spp. (1065 endemics), SE Asia with 430 spp. (260 endemics), S Asia with 172 spp. (50 endemics), Former Soviet Union with 843 spp. (565 endemics) and African continent with 83 spp. (16 endemics) are the primary and main biggest center of endemism and diversity center, while  America with 538 spp. (516 endemics) in spite of very large surface and high number of endemism seems to be the secondary center of diversity. Enumerating of species densities, showing that species richness of endemism and center of speciation and development are concentrated in SW Asia in very vast surfaces, for example Turkey with 431 spp. (260 endemics), Iran with 842 spp. (606 endemics), Afghanistan with 309 spp. (141 endemics), Middle Asia with 595 spp. (237 endemics and E Asia (only China) with 393 spp. (241 endemics) are divided as follow:

1. SW Asia (Turkey, Iran and Afghanistan with 1511 (1065 endemics)

2. Middle Asia (five countries) with 595 (237 endemics)

3. SE Asia (only China) with 393 (241 endemics)

are the primary centers of diversity, which extend toward Himalaya and Tian-Shan large mountain rang.

4. In America with 743 (> 600 endemics) despite of high number of endemism and the large surface of territory in the reason of evolutionary history (Neo-Astragalus) will be the secondary of diversity and speciation center (Table 1).

The results of this investigation provided from 55000 records of database from Old World and the distribution pattern using ArcGIS have been provided in Figure 2.

Table 1: Distribution of species in different major area

Area/Species No. of species No. of  endemics
SW Asia 1526 1062
   Turkey 431 257
    Iran 856 610
    Afghanistan 317 143
SE Asia 427 266
     China 390 241
     Mongolia 76 22
S Asia

Pakistan, India, Nepal, Buhtan

172 48
Middle Asia 605 241
   Turkmenistan 118 25
   Kazakistan 281 75
   Kyrkizistan 125 24
   Tajikistan 227 72
   Uzbekistan 207 45
Europe 134 59
Africa 83 16
America 538 520

Ali, S. E & ??, (1980), Flora Pakistan, vol. 100

Barneby, R. (1964). Atlas of North American Astragalus. Memoirs of the New York Botanical Garden 13: 1–1188.

Breckle, S. W., Hedge, I and Rafiqpoor, M. D. (2013),Vascular plants of Afghanistan an augmented Checklist: 294-317.

Chaudhary, L. B., (2018)- A Revision of the genus Astragalus (Papilionacea) in India.

Davis, (1970). Flora of Turkey, vol. 2.

Frodin, (2004)- ??

Gontscharov, (1965). Flora USSR, vol. 12.

Johnes, M. E. (1923)- Revision of North American Species of Astragalus, 1-288

Khassanov, F., (2018)- Per. comm.

Kazempour Osaloo S., Maassoumi A.A., Murakami N. (2003). Molecular systematics of the genus AstragalusL. (Fabaceae): phylogenetic analyses of nuclear ribosomal DNA internal transcribed spacers and chloroplast gene ndhF sequences. Plant Syst Evol 242: 1–32.

Kazempour Osaloo S., Maassoumi A.A., Murakami N. (2005). Molecular Systematics of the Old World Astragalus (Fabaceae) as inferred from nrDNA ITS sequence data. Brittonia 57: 367–381.

Kumar, S. and Sane, P.V. (2003). Legumes of South Asia, A checklist 535 pp.

Lock, G. M. (1991) Check list, Legumes of West Asia, 263 pp.

Maassoumi A. A., Sh. Kazempour Osaloo, A. Sotoodeh (2016). A new infrageneric grouping of Astragalus (Fabaceae). The Iranian Journal of Botany, 22: 88-100.

Maassoumi, A. A.-2003 -Flora of Iran in Persian language, no. 43: 1-384 (2003). (Book).

Maassoumi, A. A.-2016 -Flora of Iran in Persian language, no. 85: 1-504 (2016). (Book).

Maassoumi, A. A.-2018 -Flora of Iran in Persian language, no. 145: 1-766(2018). (Book).

Maassoumi, A. A. (1998) Astragalus in the Old World, A check-list  617 pp.

Podlech, D. (1999) Flora Iranica no. 174, vol.1: 1–350.

Podlech, D & Xu. (2010)- Flora of China

Podlech, D. & Zarre, Sh., (2013) with collaboration of M. Ekici, Ankara, A.A. Maaassoumi, Tehran and A. Sytin, St. Petersburg, A taxonomic Revision of the genus Astragalus in the Old World. 2439 pp.

Podlech, D. Zarre, Sh & Maassoumi, A. A. (2001). Flora Iranica  no. 175, vol.2.: 1–197.

Podlech, D., A. A. Maassoumi, A. A. & Zarre, Sh. (2012). Supplement Flora Iranica no. 179: vol. 5:1–312

Podlech, D., Zarre, Sh., Maassoumi, A. A., Sytin, A. & Ekici, M. (2010). Flora Iranica  no. 178: vol. 4:1–430 (Text); 1–375 (Tables).

Rydberg, P. 1929. Astragalaneae. Pp. 251–462. In: North American Flora. 24: parts 5, 6, and 7.

Wojciechowski, M.F., Lavin, M. & Sanderson, M.J. A phylogeny of legumes (Leguminosae) based on analysis of the plastid matK gene resolves many well-supported subclades within the family. Am. J. Bot. 91, 18461862 (2004).

Yakovlev, G. P., A. K. Sytin, and Yu R. Roskov (1996). Legumes of Northern Eurasia, a checklist. 724 pp.

Figure