Tongoloa arguta L.J.Gui & X.J.He, 2020

Gui, Ling-Jian, Wen, Jun, Xiao, Yan-Ping, Ren, Ting, Zheng, Hong-Yi & He, Xing-Jin, 2020, Tongoloa arguta (Apiaceae), a new species from southwest China, PhytoKeys 164, pp. 11-19 : 11

Tongoloa arguta L.J.Gui & X.J.He sp. nov. Figs 2 , 3 , Table 2

Type.

China. Sichuan: Kangding, Zheduoshan Pass, 4300 m alt., 30°4'N, 101°48'E, 26 Sep 2019, Lingjian Gui GLJ19092601 (holotype: SZ).

Diagnosis.

Tongoloa arguta sp. nov. is morphologically similar to T. silaifolia . However, the new species can be distinguished from the latter by its short stems (10-50 cm), while T. silaifolia has longer ones (28-60 cm); The ultimate segments of the lower leaf of T. arguta are acute and short (1-4 mm), while those of T. silaifolia are linear and longer (5-18 mm). The umbels of T. arguta have 3-8 rays, which are significantly less than those of T. silaifolia (8-22).

Description.

Plants 10-50 cm. Root usually long-conic. Stem thinly ribbed, glabrous, purplish to green, branched. Leaf sheaths inflated, membranous; blade triangular in outline, 3-5 × 2-3.5 cm, 2-3-ternate/pinnate; ultimate segments lanceolate, 1-4 × 1-2 mm, apex acute. Umbels terminal or lateral; bracts often absent or sometimes 1, leaf-like, ca. 2-4 × 1 cm, bracteoles absent; rays 3-8; umbellules 13-25-flowered. Calyx teeth minute; petals obovate, white to purple, apex obtuse; stylopodium depressed, dark purple; styles short, reflexed. Fruit broadly ovoid, ca. 2 × 1.7 mm, base cordate; ribs 5, filiform; vittae 3 in each furrow, ca. 4 on commissure. Ventral surface of endosperm slightly concave to plane.

Etymology.

The species epithet " arguta " was given to describe the acute tips of the ultimate segments of leaves.

Phenology.

The species was observed flowering from August to September and fruiting from September to October.

Distribution and habitat.

Tongoloa arguta is distributed from Sichuan (Kangding, Yajing) to Yunnan (Deqin, Shangri-la) in south-western China. It grows in alpine bushes and meadow s from 4000 m up to 4500 m alt.

Additional specimens examined.

China. Sichuan: Kangding, Xinduqiao, Zheduoshan, 4000 m alt., 3 Sep 1982, Taichang Wei 29664 (CDBI0095011); Kangding, north slope of Zheduoshan, 4000 m alt., 22 Sep 1984, Yongjiang Li 454 (CDBI0172327); Yajiang County, Jianziwanshan, 4400 m alt., 28 Sep 2019, Lingjian Gui & Chang Peng GLJ19092802 (SZ); Yajiang County, Kazilashan, 4400 m alt., 20 Sep 2018, Lingjian Gui GLJ18092002 (SZ). Yunnan: Deqin County, Baimaxueshan pass, 4350 m alt., 21 Aug 2018, Lingjian Gui GLJ18082102 (SZ); Shangri-la, Daxueshan pass, 4340 m alt., Yanping Xiao A11 (SZ); Zhongdian, Deqen, Beima Shan, on the south side of road, 4675 m alt., 25 Sep 1994, ACE 1287 (PE00755697).

Conservation status.

Tongoloa arguta is common in some alpine bushes and meadows at an altitude of about 4300 m in Yunnan and Sichuan, where human activities and especially yak grazing pose a potential threat to its survival. We categorise T. arguta as Near Threatened (NT), according to IUCN (2019).

Figures

Figure 2. Tongoloa arguta sp. nov. A species habitat (Mt. Jianziwanshan, Sichuan, China) B plant in the bush surrounded by snow C plant D-F roots G, H basal leaf, ventral and dorsal view I membranous sheath of basal leaves J middle leaf K upper leaf with membranous petiole L umbel and bract M-O flowers; P-R fruits S mericarp transverse section.

Figure 3. Tongoloa arguta sp. nov. A habit B root C basal leaf blade D leaf-like bract, only appears in some individuals E flower F fruit G mericarp transverse section. Drawn by Bing-yan Chen.