Atriplex flabellum Bunge in Boiss., Fl. Orient. 4: 912 (1879).

Sukhorukov, Alexander P., Kushunina, Maria & Sennikov, Alexander N., 2022, A new classification of C 4 - Atriplex species in Russia, with the first alien record of Atriplex flabellum (Chenopodiaceae, Amaranthaceae) from North Siberia, PhytoKeys 202, pp. 59-72 : 59

Atriplex flabellum Bunge in Boiss., Fl. Orient. 4: 912 (1879).

Obione flabellum ≡ Obione flabellum (Bunge) Ulbr. in Engler & Prantl, Nat. Pflanzenfam., ed. 2, 16c: 506 (1934). Type: Iran. "Persia, in montosis salsis ad orientem urbis Meschhed, inter Faz et Tabatkuh prov. Khorassan", A. Bunge (LE!, lectotype designated by Sukhorukov (2006: 408)).

Morphology.

For a detailed description, see Iljin (1936), Hedge (1997) and Sukhorukov (2006). The species is recognisable in all stages by its (sub)opposite crenate leaves with the Kranz-type anatomy, and flabellate and stalked bract-like covers of the female flowers with ventrally fused valves. The (sub)opposite leaves are very rarely found in the C4-clade of Atriplex , and the ventral valve fusion is present only in two Eurasian species of the genus, A. flabellum and A. moneta .

Specimen seen

(Fig. 3 ). Russia, Tyumen Oblast, Yamalo-Nenetsky Autonomous District, Novy Urengoy Town, Aug 199X [year unknown], P. Zhmylyov & S. Elansky s.n. (MW0058941!). Image available at https://plant.depo.msu.ru/public/scan.jpg?pcode=MW0058941.

Habitat.

In Russia, the species occupies ruderal habitats. Within its native distribution range, it occurs in the desert zone on sandy and loamy soils in lowlands and foothills.

Introduction status.

Casual alien. Atriplex flabellum is a typical desert plant, and its populations cannot become established in the extreme north of the boreal zone. For this reason, we presume that this population is most likely extinct now.

Native distribution.

Afghanistan, Iran, Kazakhstan (south and south-east), Kyrgyzstan, Tajikistan, Turkmenistan, Uzbekistan.

Alien distribution.

Russia (Tyumen Oblast) (Fig. 4 ).

Taxonomy.

The phylogenetic position of A. flabellum is distant to both A. sect. Obione and A. sect. Obionopsis ; this species belongs to the basal grade within a large clade encompassing the majority of the Old World species of the genus ( Žerdoner Čalasan et al. 2022). It was assigned to A. subgen. Pterotheca (Aellen) Sukhor. (lectotype species: A. moneta Bunge ( Sukhorukov 2006)), whose monophyly has not been confirmed, and the sectional placement of A. flabellum has not been evaluated. A new classification of Atriplex is currently in preparation by Sukhorukov et al.

This Russian record of Atriplex flabellum is unexpected. Two more species of the C4-clade of Atriplex , A. dimorphostegia and A. pungens (both belonging to A. sect. Obionopsis ), occur in West Kazakhstan at their western distribution limit (more detail in Sukhorukov 2006) and can potentially be found in adjacent regions of Russia (e.g., Astrakhan Oblast) as alien or sporadically distributed native plants.

Figures

Figure 3. The voucher specimen of Atriplex flabellum recorded in Russia.

Figure 4. The location of a single alien record of Atriplex flabellum in Russia.