Salsola austrotibetica Sukhor., 2019

Sukhorukov, Alexander P., Liu, Pei-Liang & Kushunina, Maria, 2019, Taxonomic revision of Chenopodiaceae in Himalaya and Tibet, PhytoKeys 116, pp. 1-141 : 115-116

5. Salsola austrotibetica Sukhor. sp. nov.

= Salsola ikonnikovii sensu Rilke (1999) non Iljin; Salsola tragus sensu Zhu et al. (2003) non L. Holotype: [CHINA, Xizang, Nyingchi Prefecture, Gongbo’gyamda County] Kongbo Province [Kongpo Region], Sang, Tsangpo valley, 29°29'N, 94°14'E, 9500 ft a.s.l., 25 Jun 1938, F. Ludlow, G. Sherriff & G. Taylor 4983 (BM000016629). Fig. 49 .

Taxonomic notes.

The hardness of the conus (perianth part above the wings or tubercles at the fruiting stage) is a very important trait for identifying the representatives of the Salsola type section (ex- Kali), which is widely used in taxonomic treatments (e.g. Iljin 1936, Tzvelev 1996, Rilke 1999). The length of the conus seems to be another important characteristic for the taxonomy of this group. All specimens of S. austrotibetica were formerly identified as Salsola ikonnikovii or rarely S. tragus (incl. S. pestifer ). The identification of the Tibetan specimens as S. ikonnikovii ( Rilke 1999) was mostly based on the similar broader and stiff leaves. Salsola ikonnikovii was formerly considered more broadly with a vast distribution covering Central Asia and Tibet ( Rilke 1999). Although some other Central Asiatic species were included in S. ikonnikovii ( S. beticolor Iljin, S. centralasiatica Iljin, S. microkali Popov, S. potaninii Iljin and S. chinghaiensis A.J.Li), the specific status of these taxa must be re-evaluated following extensive molecular and morphological investigations. All southernmost records of Salsola ikonnikovii cited by Rilke (1999) from Tibet [Xizang] are here considered Salsola austrotibetica .

Salsola ikonnikovii s. str. is characterised by a large (10-20 cm) main inflorescence with very densely arranged flowers, winged perianth 5.0-8.0 mm in diameter and peri anth segments forming a narrowly triangular and stiff conus of (2)2.5-3.5 mm long. In contrast, the new species has a much smaller (up to 12 cm) inflorescence, perianth with wings 4.0-5.0 mm across and triangular and slightly hardened perianth conus 1.5-2.0 mm long. All plants in the PE herbarium were identified as Salsola ruthenica [≡ S. tragus ], another similar-looking species. However, linear or filiform leaves and a completely hyaline perianth conus distinguish S. tragus from both S. ikonnikovii and S. austrotibetica .

The distribution area of Salsola austrotibetica is restricted to South Tibet (Fig. 48 ) and that of S. ikonnikovii covers Mongolia and the northernmost provinces of China (Nei Mongol, Ningxia and Gansu).

Description.

Annual up to 40 cm high. Stem straight, branched from the base with ascending lateral shoots; stem and leaves finely papillate. Leaves on the main stem remote (with internodes 20-40 mm long), 20-50 mm long, 1.0-4.0(5.0) mm wide above the broad base, slightly flattened, lanceolate to linear, thick, with a mucro (1.0)1.5-2.5 mm long. Flowers in axillary clusters and arranged in the main inflorescence. Flower clusters (usually located below the main inflorescence) consist of two often unequal female flowers, each flower supported by a bract and two bracteoles, sometimes additional bracts are present in the clusters; bracts and bracteoles fused in their basal part; perianth segments of each flower membranous, r-shaped, their tips appressed to each other, not hardened, not forming a conus, with red to pinkish, small or hardly noticeable wing-like tubercles in the flexure; styles with stigmas ca. 1.5 mm long; fruits 1.0 to 1.6 mm, depressed roundish to ovoid. Flowers in the main inflorescence lax, hermaphrodite, with two bracteoles (slightly shorter than bract) and a free bract having a broad (up to 1.0 mm) white margin; perianth segments membranous, tubuliform (not r-shaped), 1.7-2.2 mm at flowering stage and elongated to 4.0-5.0 mm at fruiting, their lower part marginally glabrous or finely fimbriate; segment tips slightly hardened but not hyaline, forming a convergent, glabrous conus 1.5-2.0 mm long, with well-developed, obliquely orientated, unequal, erose to lobate wings in the flexure; the whole diaspore with the perianth wings is 4.0-5.0 mm across; anthers 0.7-0.8 mm; styles with stigmas 1.3-1.7 mm; fruit ~1.5 mm, depressed roundish. Seeds with horizontal embryo.

Habitat.

Sand dunes, gravelly substrates, and sometimes in dump areas at altitudes of 2700-4200 m.

Phenology.

Flowering: July-August; fruiting: August-September.

Distribution.

See Fig. 48 .

Specimens examined.

CHINA: Xizang: Xigazê Prefecture: Gyangtse, 1904, H.J. Walton s.n. (BM); Lhasa City: Reting, 60 miles N of Lhasa, 13000 ft a.s.l., 31 Jul 1942, F. Ludlow & G. Sherriff 8986 (BM, LE); Lhasa, nr the 49th Hospital, 3700 m a.s.l., 7 Sep 1960, Xia & Zhu 816 (PE00528532, PE00528533); Shannan Prefecture: Gonggar (Gongga) County, Jêdêxoi (Jiedexiu) town, 3600 m a.s.l., 31 Aug 1975, anonym 75-1536 (PE00541011, PE00541012, PE00541013).

General distribution.

Endemic to South Tibet.

Figures

Figure 48. Distribution map of Salsola tragus (circles), S. austrotibetica (stars) and S. monoptera (triangles).

Figure 49. Holotype of Salsola austrotibetica Sukhor. sp. nov. (BM 0000016629).