Gentiana shangwui H. F. Cao & L. Zhang sp. nov.

Fig. 6, Suppl. material 1: fig. S 5

Type.

China • Sichuan: Aba Tibetan and Qiang Autonomous Prefecture, Wenchuan County, Wolong Town, Balang Mountain, 4000 m, 27 July 2018, Lei Zhang 2018 ZL 0727 (holotype: CSH!, isotype: PE 02402080!, KUN!).

Diagnosis.

Gentiana shangwui is morphologically similar to G. nanobella and G. piasezkii, but can be easily distinguished from them by having hirsute (sometimes glabrescent) leaves, and a 4–6 mm long style (vs. 1.2–2 mm long in G. nanobella and 2–4 mm long in G. piasezkii). It can be distinguished from G. nanobella by its slightly obovate-elliptic, 6–6.5 mm long capsules which are conspicuously narrowly winged along the sutures at the apex (vs cylindrical to narrowly ellipsoid, 10–12 mm long, not winged), a minutely and densely reticulate seed coat (vs. seed edges several, irregular, and spongy). It can be further distinguished from G. piasezkii by the suborbicular leaf blades with basal leaves 3–6.5 × 2–3 mm and stem leaves 2–4 × 2–3.5 mm (vs. leaf blade lanceolate, narrowly elliptic, rarely ovate, basal leaves involucriform, 17–20 × 4–6 mm and stem leaves 5–9 × 2–3 mm), the 2.5–3.3 mm long corolla lobes (vs. 4–5 mm long) and the stamens inserted in the apical part of corolla tube (vs. at middle of corolla tube).

Description.

Annual herbs, 2–6 cm tall. Stems yellowish-green or purplish-red and densely papillate, ascending to erect, branched from base. Basal leaves withered at anthesis, 3–6.5 × 2–3 mm, usually slightly larger than upper stem leaves, leaf blade oblong-ovate or ovate-lanceolate, apex rounded or acute, both surfaces glabrous, margin smooth to ciliolate and cartilaginous, sessile or with petiole up to 1.5 mm long. Stem leaves green or purplish-red, opposite, petiole 0.5–2.5 mm long, base connate into a 0.5–1 mm long tube, hirsute; leaf blade widely spaced, apex rounded and cuspidate, both surfaces puberulent and glabrescent, or sometimes abaxially puberulent on the midvein and adaxially glabrous, margin smooth to ciliolate and cartilaginous, midvein abaxially distinct; lower stem leaves 2–4 × 1.0– 3.1 mm, ovate-lanceolate to suborbicular; middle and upper stem leaves 2–4 × 2–3.5 mm, suborbicular, larger toward upper stem, shorter to longer than internodes. Flowers few to many. Pedicels yellowish-green or slightly purplish-red and densely papillate, 1–6 mm long, usually surrounded by upper leaves, rarely exposed. Calyx tubular to narrowly obconic, 9–12 mm long, outside puberulent and glabrescent; tube tubular, 7–9 mm long; lobes triangular, 1.8–2.5 mm long, margin narrowly membranous and smooth, apex acute and cuspidate, midvein strongly keeled and decurrent into conspicuous wings of calyx tube. Corolla dark blue or blue-purple, with yellow-white base, throat with dark blue-purple spots or blotches, rarely immaculate; outside upper tinged blackish-blue; middle of corolla tube bright yellow or pale yellow, with fine blackish-blue obconic streaks, tubular to narrowly funnelform, 15–20 mm long; lobes ovate, 2.5–3 × 1.5–2 mm, margin entire, apex obtuse; plicae ovate, regular or slightly oblique, 1.5–2.5 × 2–2.8 mm, margin erose, apex obtuse. Stamens inserted at apical part of corolla tube, about 9–12 mm from the base and 4.5–5.5 mm from the upper part of the tube, equal; filaments filiform, 4.5–5.5 mm long, white; anthers purplish red, pink, or yellow, 0.8–1.2 mm long, ellipsoid. Ovary oblanceolate, 4–6 mm long, apex acute, base gradually narrowing. Style 4–6 mm long, linear, 2 - lobed, lobes revolute. Capsule 6–6.5 mm long, narrowly obovoid to narrowly ellipsoid, apex long attenuate, with extremely narrow, translucent wings along both lateral margins at both ends, absent in the middle, base obtuse-rounded; gynophore up to 8 mm long. Seeds light brown, ellipsoid, 1.0– 1.5 mm long, 0.4–0.8 mm wide, coat minutely and densely reticulate.

Phenology.

Flowering and fruiting from July to September.

Distribution and habitat.

Gentiana shangwui is currently known only from its type locality in Wolong Town, Wenchuan County, and Siguniangshan Town, Xiaojin County, Aba Tibetan and Qiang Autonomous Prefecture City, Sichuan, China. It grows in alpine meadows of Balang Mountain, at an elevation of 3800–4500 m (Fig. 1).

Etymology.

This species is dedicated to the late Prof. Shangwu Liu in recognition of his outstanding expertise in Gentianaceae and his generous guidance provided to the first author (H. F. Cao).

Vernacular name.

Chinese mandarin: shang wu long dan (尚武龙胆).

Preliminary conservation status.

Gentiana shangwui is currently known only from its type locality in Siguniangshan Town, Xiaojin County, Aba Tibetan and Qiang Autonomous Prefecture City, Sichuan, China. Only four specimens, collected from 2015 onwards, exist, but since these are from a nearby locality, it is impossible to calculate the Extent of Occurrence (EOO). The Area of Occupancy (AOO) is 4 km 2, and the species is known only from a single location. These conditions qualify the species for the Critically Endangered category under IUCN Criterion B 2 and subcriterion B 2 a.

Gentiana shangwui occurs on Balang Mountain within Wolong Nature Reserve, where the habitat is well preserved and suitable for the survival of the species. Therefore, this species should be assessed as Endangered (EN B 2 abiii) (IUCN 2024).

Additional specimens examined.

China • Sichuan: Aba Tibetan and Qiang Autonomous Prefecture, Xiaojin County, Siguniangshan Town, Balang Mountain, 3800 m, 5 August 2022, Xiaodong Huang Emily 202237 (CSH 0210079!, SMCM!). • Aba Tibetan and Qiang Autonomous Prefecture, Xiaojin County, Siguniangshan Town, Balang Mountain, 30.91590833°N, 102.88571944°E, 4500 m, 14 September 2015, FLPH Sichuan Expedition 153018 (PE 02284225!; PE 02284304!). • Aba Tibetan and Qiang Autonomous Prefecture, Xiaojin County, Siguniangshan Town, Balang Mountain, 30.917912°N, 102.885317°E, 4414 m, 12 August 2018, W. G. Sun, X. G. Ma et al. FSC- 219 (KUN!).

Notes.

The most diagnostic characters of the new species Gentiana shangwui are its long style (4–6 mm long), cauline leaves pubescent on both surfaces, and the yellow or orange-yellow corolla tube at the middle part; these features readily distinguish it from other closely related congeners. Gentiana shangwui is often misidentified as G. nanobella due to their great similarities in overall morphology and foliar characters, but differs in having oblanceolate capsules with narrowly winged apices and seeds with fine reticulations (vs. linear-cylindric capsules without narrowly winged apices and vesicular seeds in G. nanobella). It also shares certain similarities with G. piasezkii in capsule morphology and the characters of corolla and calyx, yet is easily distinguished from the latter by its smaller plant size, deep blue corolla with irregularly short linear maculations, broadly ovate cauline leaves, and smaller basal leaves. G. winchuanensis is distinctly different from G. shangwui in having larger corollas and broadly ovate cauline leaves. Based on the protologue and photocopied images of the holotype of G. aphrosperma, this taxon is characterized by linear-cylindric capsules without apical wings and vesicular seeds, which are consistent with the diagnostic features of G. nanobella; thus, it is appropriate to reduce G. aphrosperma to a synonym of G. nanobella. Field observations revealed that G. nanobella exhibits considerable morphological variations in corolla color, corolla size, presence or absence of maculations, and seed size among different populations, whereas its capsule, leaf and corolla morphologies are relatively stable. Such morphological variations of G. nanobella merit further investigation.