New species: Astra­galus italicus and Astra­galus vallium-aridarum

Astra­galus onobrychis is a morpho­log­i­cally and cyto­log­i­cally diverse steppe plant that is widely distrib­uted in extra-zonal and zonal steppes from the Western Alps to the Altai. In the present study, the genetic and morpho­log­ical differ­ences between popu­la­tions in the Alps and the Apen­nines were inves­ti­gated, resulting in the descrip­tion of two new species: Astra­galus italicus (tetraploid, endemic to the south-eastern Alps and the Apen­ni­nes) and Astra­galus vallium-aridarum (octo­ploid, endemic to the Alps).

Astragalus vallium-aridarum and A. italicus differ from A. onobrychis s.str. both genetically and morphologically.

A. vallium-aridarum is a hybrid species resulting from a croosing of of different ploidy levels between the octoploid A. onobrychis and the tetraploid A. italicus. Morphometric analyses revealed significantly different characteristics between the three species. 

The two new species replace Astragalus onobrychis s. str. in the Western Alps, thereby reducing its range.

E. Huber, C. Maylandt, K. Pagitz, P. Schönswetter (2026): An integrative approach underlines the genomic and morphological divergence of Alpine and Apennine populations of Astragalus onobrychis (Fabaceae), supporting the description of two new species. Perspectives in Plant Ecology, Evolution and Systematics, Volume 73. 10.1016/j.ppees.2026.125965

Identification key for the species of the A. onobrychis-complex, found in the Alps, the Pannonian Basin and the Apennine Peninsula

Bracts and traits of well-developed flowers are examined in the middle part of the inflorescence. 

1Bracts (3.2) 4.0–6.7 (8.6) mm long; lower lateral calyx tooth 2.6–3.8 (5.2) mm long; inflorescences with (24) 26–41 (44) flowers  (Pannonian Basin)………… A. onobrychis s. str.

1*Bracts (1.6) 2.1–3.9 (5.3) mm long; lower lateral calyx tooth (0.9) 1.6–2.7 (3.8) mm long; inflorescences with (11) 14–29 (34) flowers…………2

2    Standard (16) 17.2–20.7 (23) mm long; wings (10.4) 11.8–13.9 (14.7) mm long; pistil (7.8) 9.4–11.5 (12.3) mm long; (South-Eastern Alps, Northern and Central Apennines) ………… A. italicus

2*Standard (18.1) 20.5–26.7 (28.8) mm long; wings (11.9) 13.5–16.5 (18.2) mm long; pistil (9.0) 11.1–13.5 (15.1) mm long; (Western and Central Alps, Provence) …………. A. vallium-aridarum

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