Metagentiana jiangyouensis H. F. Cao, 2024

Cao, Hai-Feng, Cai, Jie, Zou, Yuan, Sun, Hong, Li, Fang-Fang, Xiong, An-dong & Xu, Mei-Jun, 2024, Metagentiana jiangyouensis, a new species of Metagentiana (Gentianaceae) from Sichuan, China, PhytoKeys 247, pp. 137-144 : 137-144

Metagentiana jiangyouensis H. F. Cao sp. nov.

Figs 1 , 2

Diagnosis.

Metagentiana jiangyouensis is similar to M. villifera and M. rhodantha , but differs from these species by the fact that the plant is completely glabrous and has green flowering stems 8–11 cm long with 6–9 pairs of leaves per stem, well-developed basal vegetative rosettes, glabrous stem leaves with entire margin, spatulate to lanceolate, 1.3–2 (– 3) mm long calyx lobes with glabrous margins, a pale purple corolla with dark purple spots on the tube, and erose or denticulate, but never fringed plicae margins.

Type.

China • Sichuan: Mianyang City, Jiangyou County, Hanzeng Town, Qianyuan Mountain, on the road to Yinguangdong , growing on a cliff; 31.847981 ° N, 104.608385 ° E; 1169 m a. s. l.; 5 January 2019; Yuan Zou QYS 01 (holotype: CSH!; isotype: KUN 1584155 !, PE 02402078 !, SMCM!) .

Description.

Perennial herbs, 8–11 cm tall, with a short rhizome, 5–20 mm long. Flowering branches 1–4, arising from basal rosette, stems green, glabrous, ascending to erect, slender, simple or branched in upper part, 0.5–1.0 mm in diameter when fresh and 0.4–0.6 mm in diameter when dried, each stem with 6–9 pairs of leaves. Basal rosette leaves well-developed and persistent at anthesis; petiole 4–10 mm long, leaf blade oblong-spatulate or elliptic, 10–30 × 2.5–7 mm, both surfaces glabrous, margin entire, apex acute, midvein distinct. Abbreviated vegetative shoots well-developed. Stem leaves widely spaced, shorter than internodes, sessile; blade ovate, elliptic, oblong to oblong-spatulate in basal cauline leaves, and ovate to broadly ovate in middle and upper cauline leaves, 7–12 × 3–7 mm, both surfaces glabrous, margin entire, base rounded, apex acute or obtuse, veins 1–3, base tapering into a short petiole, 0.5–2 mm long. Flowers terminal, solitary, sessile, floral bracts ovate, 7–10 × 4–6 mm, both surfaces glabrous, margin entire, base rounded, apex acute or obtuse, veins 1–3. Calyx tube broadly tubular to tubular-campanulate, glabrous outside, 6–7 mm long, membranous, with 5 prominent green veins but not winged; lobes spatulate to lanceolate, equal or unequal, 1.3–2 (– 3) × 0.4–0.8 (– 1.5) mm, base usually slightly shrunken, margin cartilaginous and smooth, apex acuminate, midvein outside prominent, sinus between lobes rounded. Corolla purple, with dark purple spots on corolla tube, 2.9–3.3 cm long, tube funnel-shaped; lobes ovate-triangular, 4.5–6 × 4.5–6 mm, margin entire, apex acute; plicae obliquely truncate or broadly ovate-triangular, 2–3 × 5–6 mm, margin erose or denticulate. Stamens inserted at basal part of corolla tube, unequal; filaments filiform, 10–18 mm long; anthers deep purple, narrowly ellipsoid, 1.2–1.5 × 0.4–0.8 mm. Ovary narrowly ellipsoid, 6–10 mm long; gynophore to 5 mm long, stout. Style filiform, 9–11 mm long; stigma lobes linear. Capsules ellipsoid, 10–15 mm long, gynophore 5–10 mm long at maturity. Seeds brown, triquetrous with three narrowly winged edges, 1.1–1.5 × 0.6–0.85 mm, seedcoat coarsely reticulate.

Phenology.

Flowering and fruiting from December to April.

Distribution and habitat.

Metagentiana jiangyouensis is currently known only from its type locality in Hanzeng Town, Jiangyou County, Mianyang City, Sichuan, China. It grows on a cliff, at an elevation between 1160 and 1513 m.

Etymology.

The specific epithet “ jiangyouensis ” refers to Jiangyou County, Mianyang City, Sichuan, China, the type locality of Metagentiana jiangyouensis .

Vernacular name.

Chinese mandarin: jiang you xia rui long dan (江油狭蕊龙胆).

Preliminary conservation status.

Metagentiana jiangyouensis is currently known only from its type locality in Hanzeng Town, Jiangyou County, Mianyang City, Sichuan. Based on our field survey, the habitat of M. jiangyouensis has been frequently disturbed by anthropogenic activities and might be compromised by touristic development. Therefore, M. jiangyouensis should be considered as Vulnerable ( VU D 2) ( IUCN 2024).

Additional specimens examined

(paratypes). China • Sichuan: Mianyang City, Jiangyou County, Hanzeng Town, Qianyuan Mountain, near the Yinguangdong , growing on a cliff or on mossy rocks, 31.849795 ° N, 104.611639 ° E, 1456 m, 5 January 2019, Yuan Zou QYS 02 (paratypes: CSH!) • Same locality, 31.849402 ° N, 104.612286 ° E, 1513 m, 23 March 2024, Hai-Feng Cao CAOHF 033 ( CSH!, KUN!, PE!, SMCM!) • Same locality, 1160–1180 m, 4 March 2024, Ang Liu & Chao-Ling Yang LAJY 01 ( CSFI, image!) .

Figures

Figure 1. Metagentiana jiangyouensis H. F. Cao A habit B longitudinally opened corolla C pistil D longitudinally opened calyx E middle or upper cauline leaf F seed G, H closed and open fruit. Drawn by H. F. Cao A – E Yuan Zou QYS 01 F – H Hai-Feng Cao CAOHF 033.

Figure 2. A, B habitat C habit D vegetative rosettes E seedling F stem G corolla, front view H calyx, side view I cauline leaves, adaxial view J fruits K opened fresh flower L seeds. Scale bars: 2 cm (C); 1 cm (D – G, J, K); 5 mm (H, I); 1 mm (L). A, B photographed by Y. Zou C – L photographed by H. F. Cao A – I, K Yuan Zou QYS 01 J, L Hai-Feng Cao CAOHF 033.