Stipa arenosa (Tzvelev) M. Nobis, P.D. Gudkova, Krzempek & Klichowska, comb. and, 2022

Nobis, Marcin, Krzempek, Marta, Nowak, Arkadiusz, Gudkova, Polina D. & Klichowska, Ewelina, 2022, Resurrection of Stipa tremula and taxonomy of the high-alpine species from the Stipa purpurea complex (Poaceae, Pooideae), PhytoKeys 196, pp. 21-47 : 21

Stipa arenosa (Tzvelev) M. Nobis, P.D. Gudkova, Krzempek & Klichowska, comb. and stat. nov.

Stipa purpurea arenosa ≡ Stipa purpurea subsp. arenosa (Tzvelev) D.F. Cui, Flora Xinjiangensis 6: 307. 1996.

Basionym.

Stipa purpurea var. arenosa Tzvelev, Rastenia Tsentral’noi Azii po materialam Botanicheskogo Instituta im. V. L. Komarova 4: 60. 1968.

Type protologue.

Tibet bor.-occid., praemontium bor. jugi Przeval’skii, ad 5000 m alt., in steppa Stipa arenosa , 24.08.1980, V. Roborovski (LE). Type: Thibet boreal.-occid., Kuen-Lun, Khr. Przeval’skogo, severnye peredgorya, 24 Aug 1890, W.J. Roborowski s.n. (holotype, LE 01010497!).

Description.

Perennial plant, densely tufted, with a few culms and numerous vegetative shoots; culms (14.7-)16.2-39.1(-50.0) cm tall, 1-2(-3)-noded, nodes distributed close together and only in the lowermost part of the culm. Leaves of vegetative shoots: sheaths shortly and densely pubescent; ligules truncate to slightly acute, on the external sheaths (0.5-)1.0-1.8(-2.3) mm long, whereas on the internal sheaths (1.0-)1.5-3.0(-4.5); blades convolute, green, pale green to glaucous, (4.9-)6.1-11.4(-16.0) cm long, 0.4-0.5 mm in diameter, adaxial surface covered by 0.15-0.2 mm long hairs, abaxial surface glabrous, scabrous or setulose. Cauline leaves: lower sheaths sparsely pubescent to almost glabrous, upper sheath glabrous or almost so; ligules acute, on the lower sheaths (0.7-)1.2-1.9 mm long, on the middle sheaths (1.6-)1.9-3.5(-4.5) and on the upper 2.0-3.45(-4.5); blades convolute, green or pale green, (2.5-)3.0-6.5(-7.8) cm long, adaxial surface covered with short hairs, abaxial surface glabrous, scabrous to shortly pubescent. Panicle (7.6-)8.7-14.4(-17.8) cm long, open, at base enclosed by the sheath of the uppermost leaf or rarely exerted, branches flexuous, setulose or slightly scabrous or glabrous, single or paired. Glumes subequal (the lower slightly longer than the upper), purplish, glumes (19.5-)21.0-23.5(-25.0) mm long, narrowly lanceolate. Floret (lemma + callus) (11.5-)12.0-14.0(-15.0) mm long. Callus (2.0-)2.3-3.0(-3.8) mm long, densely pilose on the ventral part, with hairs (0.4-)0.6-0.9(-1.0) mm long, on dorsal part sparsely and shortly pilose with straight hairs (0.5-)0.6-0.8(-0.9) mm long; callus base 0.5-0.8 mm long and 0.15-0.25 mm wide, sharply pointed, scar narrow-elliptic. Lemma coriaceous, pale-green, purplish or brownish, covered throughout (from the bottom to top) by dense ascending to appressed hairs 0.2-0.4 mm long; top of lemma surpassed by a ring of unequal hairs 0.4-0.9 mm long. Awn (78-)95-112(-130) mm long, bigeniculate, straw-coloured to brownish; first segment of the awn (column) (7-)11-22 mm long, twisted, 0.3 mm wide at base, with (1.5-)1.6-2.0(-2.3) mm long hairs, middle segment of the awn 10-12(-13) mm long, twisted, with (1.7-)1.9-2.4 mm long hairs; terminal segment of the awn (seta) arcuate or flexuous (62-)68-89(-98) mm long and, hairs longer than those on columns, (2.1-)2.3-2.5(-3.0) mm long, gradually decreasing in length towards apex. Palea equalling lemma in length.

Habitat.

High mountain steppes, semi-deserts, 3500-5000 m. a.s.l.

Distribution.

China: southern Xinjiang, Qinghai, Gansu, north-western Xizang; Fig. 3 ( Tzvelev 1968).

Selected specimen examined.

China: Qinghai Province: Kuen-Lun, Dolina r. Sharagol’ -dzhin, yr. Paidza-Tologoi, 11000 ft alt., pesch. step’, 11 Jul 1894, W.J. Roborowski 318 (LE 01010495 [label 2: Stipa purpurea Griseb f. robusta, det. R. Roshevitz; Label 3: Stipa kozlovii m. sp. nov. inedit. = S. purpurea var. Stipa purpurea arenosa m. var. nova, Typus varietis!, XI. 1966, N.N. Tzvelev], LE 01010496, KRA 476855, K, - paratypes); Xinjiang Province, Ruoqiang, N of Aqqikkol, on grasslands, ca. 4200 m alt., 21 Aug 1988, S. Wu, H. Ohba, Y. Wu, Y. Fei 2747 (MOIS 3744710); Xinjiang, Ruoqiang, Yueya River to Aqqikkol, in Stipa grassland on gravel-rich flat places, 21 Aug 1988, S. Wu, H. Ohba, Y. Wu, Y. Fei 2275 (MOIS 5660755); Gansu Province, Subei County, alt. 3500 m, 5 Aug 1956, B-z. Guo s.n. (PE 707226); Xizang Province, 16 km northeast of Shuanghu County, alt. 5000 m, 27 Jul 1976, Gansu Agricultural University 111 (PE 2029866).

Note.

Stipa purpurea var. arenosa was described, based on two collections of W.J. Roborowski from Central Asia ( Tzvelev 1968). During our research in 2009-2021, in addition to the holotype, we found four sheets (paratypes) with specimens of Stipa collected by Roborowski in 1894. The two of the paratypes preserved in LE, were labeled as the type and isotype of Stipa purpurea var. arenosa by N. Tzvelev in 1966.

Figures

Figure 3. The distribution range of Stipa purpurea (purple backgrounds and points), S. tremula (blue backgrounds and points) and S. arenosa (yellow points).