Chenopodium pamiricum Iljin, Fl. SSSR 6: 873 (1936)

Sukhorukov, Alexander P., Liu, Pei-Liang & Kushunina, Maria, 2019, Taxonomic revision of Chenopodiaceae in Himalaya and Tibet, PhytoKeys 116, pp. 1-141 : 18-19

2. Chenopodium pamiricum Iljin, Fl. SSSR 6: 873 (1936)

Holotype.

[TAJIKISTAN] Pamir Orientale, declivia ad confluentes Baital et Murgab [Bartang], [East Pamir, slopes near confluence of Baital and Murgab rivers], 1 September 1923, H. Raikova 417 (TASH - photo seen (!) and fragments of type material (!); isotype - LE!).

Taxonomic notes.

Morphologically, C. pamiricum can be easily confused with C. vulvaria , but all data on the presence of C. vulvaria in mountainous regions of Central Asia belong to C. pamiricum . In contrast to the latter species, either fresh or dry leaves of C. pamiricum do not have a scent. Further investigations have shown that the type material and many other specimens of C. pamiricum have evident heterospermy, a rare characteristic in Chenopodium s. str. discovered by Sukhorukov and Zhang (2013).

Description.

Annual up to 25 cm with several or numerous prostrate or ascending stems. Leaves farinose, shortly petiolate (petioles up to 1.5 cm but usually much smaller) with blades up to 2 cm, rhombic or ovate, entire or subhastate. Inflorescence leafy almost to the top. Flowers in glomerules arranged in ± dense inflorescence. Perianth farinose. Fruits and seeds heteromorphic. The first type of fruits and seeds is formed in terminal flowers, the fruits ripen in July-August. These fruits are ca. 1 mm in diameter and 0.5 mm thick; pericarp with papillae up to 20(25) μm (Fig. 4C ); seed dark red or blackish with median keel (Fig. 4E, F ), testa 17-25 μm thick. Fruits of the second type (which dominates at the end of the vegetation period) are ovoid, 1.0-1.2 mm long, ca. 0.5 mm thick, pericarp papillate or not (Fig. 4D ); seeds yellow-brownish, elongated.

Habitat.

Sandy or rocky places, 3400-5000 m a.s.l. (in Himalaya) and at lower altitudes in Central Asia.

Phenology.

Flowering: June-September; fruiting: August-October.

Distribution.

See Fig. 5 .

Specimens examined.

CHINA (new records for China): Xizang: Ngari Prefecture: Gê’gyai (Geji) County, Yanhu Distr., 4450-4500 m a.s.l., 24 Aug 1976, Qinghai-Tibet Team Vegetation Group 13541 (PE00235028); Rutog (Ritu) County, Rabang (Rebang), 4360 m a.s.l., 28 Aug 1976, Qinghai-Tibet Team Vegetation Group 13653 (PE00235010).

INDIA: Jammu & Kashmir: [Ladakh] Nubra [valley], Kardong [La], Aug 1856, Schlagintweit 2180 (BM); Rupshu, Rachogba, 13400 ft a.s.l., 24 Jun 1931, W. Koelz 2105 (LE); [Ladakh] Taglang La, 4820 m a.s.l., 3 Aug 1992, H. Hartmann 4014 (G455287); Ladakh, Rupshu [Plateau], Tso Kar [lake], 4600 m a.s.l., 22 Aug 1995, H. Hartmann 5037 (MSB137926); Ladakh, Zanskar Region, Ruberung La, 4300 m a.s.l., Aug 1997, L. Klimeš s.n. (PRA); Ladakh, Zanskar, Tsarap, 4180 m a.s.l., 5 Sep 1998, L. Klimeš 380 (PRA); Indus valley, Stot (E) [Stod River valley], Nyi, 4600-4700 m a.s.l., 2 Sep 2002, L. Klimeš 6176 (PRA); Ladakh, Pangong Region, Spangmik, 4300 m a.s.l., 9 Sep 2002, L. Klimeš 2676 (PRA); Indus valley, Stot (E), Sumdo Gonma to Kiagar La, 4690 m a.s.l., 7 Sep 2003, L. Klimeš 3463 (PRA); Shyok (E), Laga vill., 4220-4230 m a.s.l., 12 Sep 2003, L. Klimeš 2745 (PRA); Indus valley, Sham (W), Basgo to Nye, 3490-3590 m a.s.l., 7 Aug 2006, L. Klimeš 6712 (PRA).

General distribution.

Central Asia south to North Himalaya and North Tibet. For a long time, C. pamiricum has been considered endemic to Pamir ( Iljin 1936, Pratov 1972). The analysis of the material collected in the fruiting stage proved that the range of Chenopodium pamiricum covers almost all parts of Central Asia with records in Mongolia, West China (Xizang and Xinjiang), North Pakistan, North India, Kyrghyzstan, Tajikistan, Russia (Altay Mountains) and Eastern Kazakhstan. The records from Pamir, Karakoram, NW Tibet and North Himalaya represent the southernmost boundary of the distribution of C. pamiricum .

Figures

Figure 4. SEM micrographs of Chenopodium fruits and seeds. A, B seed of C. album C C. pamiricum, fruit with red seed D C. pamiricum, fruit with brown seed E, F C. pamiricum, red seed G, H seed of C. ficifolium. Magnification: 50 x (A, E, G), 100 x (C, D); 200 x (B, F, H).

Figure 5. Distribution map of Chenopodium album (circles) and C. pamiricum (stars).