Agriophyllum tibeticum Sukhor., 2019

Sukhorukov, Alexander P., Liu, Pei-Liang & Kushunina, Maria, 2019, Taxonomic revision of Chenopodiaceae in Himalaya and Tibet, PhytoKeys 116, pp. 1-141 : 93-95

1. Agriophyllum tibeticum Sukhor. sp. nov.

Agriophyllum tibeticum Sukhor. sp. nov. Holotype: [CHINA, Xizang, Nyingchi Prefecture] SE Tibet, Kongbo [ Gongpo’gyamda] County, Lilung-Gacha, 29°07'N, 93°41'E, 9800 ft a.s.l., on sand dunes, 5 Oct 1938, F. Ludlow, G. Sherriff & G. Taylor 7180 (BM001209885! isotypes - E! G!). Fig. 38 .

= Agriophyllum squarrosum auct. non (L.) Moq.

Taxonomic notes.

The specimens of A. tibeticum were identified as A. arenarium or A. squarrosum (both names refer to A. pungens ) because of their similar habit and oblong leaves. However, the stems of A. tibeticum are much shorter and their upper parts are covered with long (up to 2.5 mm), persistent dendroid hairs (or at least not easily caducous) at the fruiting stage. The hairs of A. pungens and A. gobicum are up to 0.8-1.0 mm long and easily caducous at the fruiting stage. Additionally, these two species are distributed in the plains of Central Asia: A. pungens is widely distributed in the Irano-Turanian Region and A. gobicum is localised in Mongolia and North China. Thus, there is a significant gap between the distribution of typically alpine A. tibeticum and all other species of the genus.

Description.

Annual up to 20(30) cm with tumble-weed habit; stem very densely pubescent with dendroid hairs (up to 2.5 mm in length, Fig. 39A ) and often whitish when young with partially persistent hairs in the fruiting stage. Lower leaves oblong or oblong-lanceolate, continuously decreasing in size and shape in the inflorescence, 2.0-8.0 × 0.5-1.5 cm, tapered in petiole, with (5)6-10 prominent nerves, densely pubescent when young. Inflorescence leafy; flower clusters remote in the lower part of the inflorescence and densely arranged in the upper part. Anthers ~0.3 mm. Pericarp covered with dendroid hairs, glabrescent at fruiting. Seed lens-shaped (Fig. 39B, C ), 1.9-2.1 mm × 1.3-1.4 mm, yellow with brownish tanniniferous spots.

Differs from the two related species, A. pungens (Vahl) Link ex A.Dietr. and A. gobicum Bunge (if the latter is accepted at the specific rank), by persistent dendroid pubescence (with longer hairs) in the inflorescence at the fruiting stage as well as by its disjunct distribution in South Tibet.

Habitat.

Sand dunes and stony riverbeds; 2800-3700 m a.s.l.

Phenology.

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

Distribution.

See Fig. 40 .

Specimens examined.

CHINA: Xizang: Lhasa City: Vicinity of Lhasa, Sep 1939, Richardson 360 (BM); Lhasa, 5 Sep 1943, F. Ludlow & G. Sherriff 9921 (BM, E, LE); Shannan Prefecture: Gonggar (Gongga) County, river bank of the Yarlung Zangbo (River), 3600 m a.s.l., 23 Sep 1975, Qinghai-Tibet Team 7659 (KUN0586383); [ Nêdong (Naidong) County] Zêtang (Zedang), 3500 m a.s.l., 10 Aug 1977, B.Z. Guo et al. 22306 (NAS00303010); [Gonggar (Gongga) County] Yarlung Zangpo at Kyi Chu junc tion, SW of Lhasa, 29°17'N, 90°41'E, 3550 m a.s.l., 12 Sep 1995, G. & S. Miehe 95-58-02 (MSB147358); Nyingchi Prefecture: Tsangpo valley, 10000-11000 ft a.s.l., 7 Sep 1935, F. Kingdon-Ward 12313 (BM); Kongbo [Kongpo] County, Temo, Tsangpo valley, 29°35'N, 94°38'E, 9500 ft a.s.l., 8 Sep 1938, F. Ludlow et al.. 6238 (BM, E); Mainling (Milin) County, Pai Distr. (town), 11 Aug 1975, Qinghai-Tibet Team Additional Group 751310 (KUN0586386); Mainling County to Nang County, 1 km W of Gyemdong, 28°59'N, 93°17'E, 3040 m a.s.l., 8 Aug 1994, B. Dickoré 10696 (MSB144288).

General distribution.

Endemic to South Tibet.

Figures

Figure 38. Holotype of Agriophyllum tibeticum Sukhor. sp. nov. (BM 001209885).

Figure 39. SEM micrographs: A Agriophyllum tibeticum, hairs from the stem B A. tibeticum, concave side of the seed C A. tibeticum, convex side of the seed D Suaeda olufsenii, fruit enclosed in the perianth; E, F S. olufsenii, red seed. Magnification: 50 x (A, B), 75 x (C, D), 100 x (E), 500 x (F).

Figure 40. Distribution map of Agriophyllum tibeticum (stars) and Suaeda olufsenii (circles).