Elymus uzbekistanicus Usupbaev & Alieva, 2025

Alieva, Kumush B., Peng, Yilong, Usupbaev, Adilet, Tojibaev, Komiljon Sh., Yusupov, Ziyoviddin, Ergashov, Ibrokhimjon, Azimova, Dilnoza & Jiang, Zhilin, 2025, Synopsis of the genus Elymus (Poaceae) in Uzbekistan (Middle Asia) with a description of Elymus uzbekistanicus a new species from Turkestan Mts, PhytoKeys 257, pp. 9-50 : 9-50

11. Elymus uzbekistanicus Usupbaev & Alieva sp. nov.

Figs 13 , 14

Type.

Uzbekistan • Jizzakh: northern slopes of the Turkestan range, upper reaches of Sanzar, Guralash-Sai reserve, on the rocky screes of Lyangar-Sai , 14 August 1937, E. E. Korotkova, A. P. Vasilkovskaya 1024 (holotype: TASH [ TASH 055342 ]!) .

Diagnosis.

Elymus uzbekistanicus differs from the morphologically closely similar E. praeruptus in the type of pubescence of the spikelet axis – the spikelet axis along the ribs and along the back is usually with either long or short hairs, but is not glabrous or bristly along the ribs (Fig. 15 ). These two species are similar in blade width 1–4 (5) mm but the leaves of E. uzbekistanicus are longitudinally rolled or more or less flat, with long, dense hairs protruding adaxial and abaxial surfaces, in contrast to the leaves of E. praeruptus , which are glabrous or covered with very short hairs on the upper surface (Fig. 16 ).

Description.

Herbs, perennial, forming dense turf, without creeping underground shoots, bluish glaucous. Stems erect, 50–100 cm, pubescent with dense, long hairs; nodes densely long-hairy. Sheaths hairy. Ligule 1–1.5 mm. Leaves 1–4 (5) mm wide, grayish green, convolute or more or less flat, both surfaces protruding densely long-hairy. Inflorescence - straight, less often slightly drooping, usually linear, (5) 10–17 (20) cm. Spikelets solitary at each node of axis of spike, all uniform (8) 10–15 (20) mm, with 3–7 bisexual florets, violet; axis of spikelet along ribs and along the back with long hairs, either at the bottom with more or less short hairs. Glumes (4) 5–7 (9) veined; upper glume 8–10 mm, lower glume 9–11 mm. Lemma 8–9 mm, adaxially with dense even spines merging into hairs; awn flexuous, to 25 mm. Palea 7–8 mm. Callus of lemma with few hairs. Anthers 2–3 mm.

Distribution and habitat.

Elymus uzbekistanicus grows on rocky screes at 2900 m. It is known only from the type locality on northern slopes of the Turkestan Range, Guralash river basin, in Jizzakh province, Uzbekistan (Fig. 17 ). Elymus uzbekistanicus belongs to the Northern Turkestan botanical-geographical region within the Kuhistan botanical-geographical district.

Etymology.

The specific epithet refers to the country, Uzbekistan.

Phenology.

Flowering and fruiting: most likely in August.

Conservation status.

Because the species is known only from the type locality it can be categorized as critically endangered according to IUCN criterion B (e. g. Alam and Ali 2010; Wagensommer et al. 2014, 2017; Le Breton et al. 2019). The restricted range of E. uzbekistanicus highlights its conservation significance and underscores the need for further studies on its population status and ecological adaptations.

Notes.

Within the genus Elymus in Uzbekistan, E. uzbekistanicus exhibits a notable morphological distinctiveness, primarily due to its significantly higher pubescence compared to other species. This characteristic is particularly evident in the leaf sheaths, stem, node, and spikelet axis, which are densely covered with hairs, distinguishing it from closely related taxa.

A specimen of E. uzbekistanicus in TASH, was identified by V. P. Drobow as Agropyron ugamicum Drobow , a synonym of Elymus nevskii Tzvelev (a quite common and widespread species), first described from the Western Tian Shan ( Tzvelev and Probatova 2019). Morphologically, these two species are also similar, sharing such features as straight spikes and lemmas that are abaxially quite densely covered with spines. In E. nevskii , however, the axis of the spikelet is rough only along the ribs, and they are abaxially glabrous. The leaf blades are usually glabrous abaxially and the nodes of the culms are always glabrous. The awn of the lemmas is up to 6 mm. Those features are all different from those of E. uzbekistanicus , as described herein (Fig. 14 ). Furthermore, such features of E. uzbekistanicus as location of leaf blades on top along thick and strongly projecting ribs and the dense short hairs, or less often spines, suggest that it belongs to sect. Anthosachne ( Tzvelev 1976) . Both phylogenetically and morphologically E. uzbekistanicus is similar to E. praeruptus , especially in the following features: grayish green, convoluted, violet-colored glumes and narrow leaf blades, as well as in the erect spikes (less often slightly drooping). The sibling relationships in the evolutionary trees based on the cpDNA genome provide evidence for the morphological similarity. However, the two species differ in the morphology of the lemma, palea, and spikelet axis (Table 1 , Figs 15 , 16 ).

Figures

Figure 13. Elymus uzbekistanicus a spike b spikelet c glumes d lemmas and paleas e stem f node g ligule.

Figure 14. The holotype of Elymus uzbekistanicus Usupbaev & Alieva, sp. nov. [TASH 055342].

Figure 15. Spikelet axis a E. uzbekistanicus – usually with long or more or less short hairs along the ribs and the back b E. praeruptus – back usually glabrous and smooth; ribs with bristles.

Figure 16. Leaf blades a E. uzbekistanicus – longitudinally rolled or more or less flat, densely covered with long, spreading hairs on both surfaces) b E. praeruptus – adaxial surface covered with short hairs or glabrous.

Figure 17. Distribution of Elymus uzbekistanicus (Turkestan Range, Uzbekistan)