Allium stoloniferum D.F. Xie & R.Y. Cheng & X.J. He, 2025

Allium stoloniferum D.F. Xie & R.Y. Cheng & X.J. He View in CoL , sp. nov. ( Figs. 1 View FIGURE 1 , 3A View FIGURE 3 )

Type:— CHINA. Sichuan: Pingwu County, arid slopes, alpine shrub ; 32°54′20.39″ N, 104°3′24.04″ E; elevation 2960 m, 22 August 2024, XDF20240822-1 (holotype SZ: SZAS001 ; isotype SZ: SZAS002 – SZAS004 ) ( Fig. 3A View FIGURE 3 ) .

Diagnosis:— Allium stoloniferum is most similar to A. paepalanthoides and A. plurifoliatum concerning morphological characters, but it can be easily distinguished by several key traits. It has cylindrical and hollow scape (vs. solid), well-developed subterranean rhizomes (vs. no subterranean rhizomes), flattened and solid leaves without prominent midvein (vs. solid leaves with a distinct, prominent midvein), leaves and scapes have a purplish-red color at the base (vs. green) and the scape is covered by leaf sheaths only at base (vs. covered by leaf sheaths for ca. 1/3–1/2 length). Additionally, A. stoloniferum differs from other closely related species in the A. sikkimense group in several notable ways: bulb type (solitary or paired vs. clustered), tunics of outer bulb (papery and splitting into strips vs. fibrous), color of fibrous roots (brown or yellow-brown vs. gray), well-developed subterranean rhizomes, scape shape (hollow vs. solid), color of tepal (pale red or pale purple to purple vs. blue), and color of tepal midvein (pale green vs. dark blue).

Description:—Perennial herbs, bulbs solitary or paired, cylindrically conical, 0.5–0.8 cm in diam., tunics brown to yellow-brown, papery, splitting into strips, sometimes nearly fibrous; fibrous roots in brown or yellow-brown, well-developed subterranean rhizomes. Leaves broadly linear to linear-lanceolate, shorter than to sub-equaling scape, leaves blade base purplish red, 15–20(–30) cm long, 2–3(–6) mm wide, apex acuminate. Scape 15–25(–30) cm long, 1–2(–3.5) mm in diam, terete and hollow, covered with leaf sheaths only at base. Scape as well as the base of the leaf

......continued on the next page blade is distinctly purplish red. Spathe 1–valved, persistent or caducous. Umbel hemispherical, laxly flowered. Pedicels nearly equal, 6–10 mm long, 1.5–2 × as long as tepals. Tepals pale red or pale purple to purple; ovate, segments with pale greenish midvein, outer tepals usually shorter and narrower than inner ones, narrowly ovate, boat-shaped, 4.5–5.5 mm long; inner tepals ovate-oblong, 4–5 mm long, apex blunt. Filaments nearly equal, white to purple, 8–10(–12.5) mm, 2 × as long as tepals, connate at the base and adnate to tepals; outer ones subulate and not broadened at base; inner ones broadened and 1–toothed on each side at base; teeth 1–1.5 mm. Anthers ovate, yellow. Ovary ovoid, green, with concave nectaries covered by curtain-like projections at the base; style exerted, 3.5–4 × as long as ovary, stigma punctiform; three locules and 2 ovules per locule. ( Figs. 1–3 View FIGURE 1 View FIGURE 3 ; Table 2).

Phenology:—Flowering from late August to September, fruiting from October to November.

Etymology:—The specific name is taken from the specialized root structure of this species, which have well-developed underground rhizomes. The type locality is Pingwu County, Sichuan Province. The Chinese name is “ ±= ¨” (zǒu jīng jiǔ).

Distribution, habitat and ecology:— Allium stoloniferum is currently known to be distributed in Pingwu County, Sichuan Province, China. It was observed to grow in the alpine shrub vegetation at an elevation between 2900 m and 3100 m.

Conservation status:—During our field investigation, we discovered only one population of this species with fewer than 500 individuals in Wanglang. Given the development of tourism in this region, it is possible that this population may be easily threatened by external factors associated with tourism. Therefore, this species is preliminarily considered as Vulnerable species (VU) according to the IUCN Red List Categories and Criteria (IUCN 2019).