A new classification of C4- Atriplex species in Russia, with the first alien record of Atriplex flabellum (Chenopodiaceae, Amaranthaceae) from North Siberia

Abstract

For a long time, the systematics of Atriplex was based solely on morphological characters and leaf anatomy. The latest worldwide phylogenetic study of Atriplex significantly improved our knowledge about the relationships within the genus, but a new classification has not been put forward thus far. Here we re-evaluate the taxonomy of C4-species of Atriplex that are native to Russia. Seven species are classified into two sections, A. sect. Obione (incl. A. sect. Sclerocalymma, syn. nov.) (A. altaica, A. centralasiatica, A. rosea, A. sibirica, and A. sphaeromorpha), and A. sect. Obionopsis (incl. A. sect. Psammophila, syn. nov.) (A. fominii and A. tatarica). Although the majority of Eurasian C4-species have similar morphology, leafy inflorescence is a typical character for A. sect. Obione. The members of A. sect. Obionopsis are characterised mostly by aphyllous inflorescences, but some species (A. laciniata, A. pratovii, and A. tornabenei) have leafy inflorescences. Geographically, almost all members of A. sect. Obione are confined to Central Asia, although A. rosea is a typical Mediterranean element and A. argentea occurs in North America. The representatives of A. sect. Obionopsis are distributed mostly in the Mediterranean and the Irano-Turanian floristic region. The alien status of A. rosea, A. sibirica and A. tatarica is discussed. Atriplex flabellum, a desert species from the Irano-Turanian region, is reported for the first time from Russia (Yamalo-Nenets Autonomous District, North Siberia) as a casual alien. This species occupies a phylogenetic position distant from both aforementioned sections. An identification key to all C4-species of the genus growing in Russia is given, and a sectional checklist with updated nomenclature and revised synonymy is provided.

Taxonomic inventory and distributions of Chenopodiaceae (Amaranthaceae s.l.) in Orenburg Region, Russia

“…It has disappeared from almost all territories of European Russia where it was collected in the 19 th and first third of 20 th centuries and all old specimens were collected in the areas located westwards of the Volga ( Sukhorukov 2006 , Sukhorukov et al 2022 ), thus outside of Orenburg Region.…”

“… Chenopodium vulvaria ) were treated in this work as occurring in the whole territory of the Transvolga Floristic Region, including Orenburg Region, which have never been reported in more detailed surveys and supported by herbarium specimens or other documented observations. Atriplex rosea was also included in this work, but treated as absent in Orenburg Region by Sukhorukov et al (2022) .…”