Gentiana daofuensis Y. M. Yuan & P. C. Fu sp. nov.

Fig. 1

Type.

China • Sichuan Province: Daofu County, near Geka Village, alt. 3810 m, 101.31°N, 30.78°E, 23 Jul 2025, flowering and with few fruits, P. C. Fu & S. S. Sun Fu 2025075 (holotype: HNWP 392646!; isotype: PE!).

Diagnosis.

Gentiana daofuensis is distinguishable from all other similar species of the genus by the combination of the reniform leaves on the upper stem and the pale blue-purple corolla with numerous dark blue short stripes or spots.

Etymology.

The specific epithet “ daofuensis ” is derived from the type locality of the new species, Daofu County, and the Latin suffix - ensis, indicating the place of origin or growth.

Vernacular name.

Chinese mandarin: dao fu xiao long dan (道孚小龙胆).

Description.

Annual herb, 3–16 cm tall. Stems ascending, often purplish-red, densely papillate, much branched from base, further repeatedly dichotomously branched. Basal leaves rapidly withering, blade ovate-elliptic or ovate, 5–12 × 3–6 mm, base rounded or cordate, apex acute and cuspidate with a recurved tip, margin thickly cartilaginous, midvein white cartilaginous, smooth, prominent beneath, petiole densely papillate on abaxial surface, 0.5–1 mm long. Stem leaves spreading or nearly perpendicular to the stem, widely spaced, petiole 0.5–1 mm, papillate, base rounded, margin thick cartilaginous, midvein prominent; middle and lower leaves ovate-triangular, 1.5–2 × 2.5–3 mm, apex acute and cuspidate with a recurved tip; upper leaves reniform, wider than long, 2–4 × 3–6 mm, apex rounded to truncate with a recurved tip. Flowers several, solitary at apex of branchlets; pedicel often purplish-red, densely papillate, 0.5–7 mm long; calyx tubular, green, 5–7 mm long, tube membranous, lobes recurved, uniform, reniform or broadly circular, 1.1–1.2 × 1.2–1.5 mm, base rounded to cordate, abruptly contracted, margin thick cartilaginous, apex rounded to truncate and mucronate with a recurved tip, midvein white, thickly cartilaginous and prominent. Corolla salverform, 1–1.4 cm long, 0.9–1.2 cm in diameter, 2.5–3 mm in diam. at throat; corolla tube narrowly tubular, base yellow to yellow-green, upper outside dark blue, inside pale blue-purple, with numerous dark blue short stripes or spots; lobes ovate, 1.5–2.3 mm long, margin entire, apex obtuse without a tip; plicae broadly ovate, 1–1.2 mm long, apex obtuse, margin entire or erose. Stamens inserted at middle of corolla tube, equal; filaments ca. 3 mm long, white; anthers narrowly oblong, ca. 0.8 mm long, yellow to violet; ovary oblong or elliptic, 3–4 mm long. Style linear, 1.5–2 mm long, white to pale green; stigma 2 - lobed, reflexed, broadly linear, white to pale green. Capsule exserted or included, oblong or obovate-oblong, 6–9 mm; gynophore to 1 cm, stout. Seeds pale brown, oblong or elliptic, 1–1.2 mm in diameter, surface with dense fine reticulations.

Phenology.

Gentiana daofuensis has a long flowering and fruiting period. We have observed flowering and fruiting from July to September.

Distribution and habitat.

Gentiana daofuensis is currently only found in Daofu County, which is located at the southeastern edge of the Qinghai – Tibet Plateau. This species usually occurs at elevations between 3,600 and 3,900 meters and mainly grows in dry or rocky roadsides, hillsides, meadows, and scrub margins. It can also occasionally be found at forest margins.

Morphological analysis.

Morphologically, G. daofuensis is most similar to G. crassuloides Bureau & Franch. as well as G. curviphylla T. N. Ho. In total, we examined two populations of G. daofuensis, four of G. crassuloides, and four of G. curviphylla. Analysis of specimens from distinct localities for each species revealed clear morphological differences among the three species (Table 1; Fig. 2). Overall, G. daofuensis most closely resembles G. crassuloides within the genus but differs from the latter in its drier habitat preference, shorter calyx, paler blue color, and the presence of short stripes or spots on the corolla (Table 1; Fig. 2). Gentiana daofuensis generally has a shorter corolla than G. crassuloides, although overlap in length is sometimes observed (Fig. 2). G. daofuensis differs from G. curviphylla in the shape of the upper stem leaves and the paler color of the corolla lobes and in the narrower corolla tube at the throat (Table 1).

Molecular phylogenetics.

The two newly sequenced chloroplast genomes of G. daofuensis range from 128,253 to 128,263 bp in length, with a GC content of 37.4 %. The lengths of the Large Single Copy (LSC), Small Single Copy (SSC), and IR are 73,073 –73,082 bp, 10,421 –10,480 bp, and 22,370 –22,381 bp, respectively. The lengths of the total chloroplast genome, LSC, SSC, and IR of G. daofuensis fell within the average range of section Chondrophyllae but were much shorter than those of other sections in Gentiana (Sun et al. 2018; Fu et al. 2022). Phylogenetic analysis included these sequences alongside 36 previously published Gentiana chloroplast genomes, 23 of which belong to G. section Chondrophyllae s. l. The resulting chloroplast genome alignment produced a well-supported phylogenetic tree, with nearly all nodes receiving full support (100 % bootstrap support; Fig. 3). All sampled species of G. section Chondrophyllae s. l. formed a monophyletic clade. The two G. daofuensis samples clustered together with G. crassuloides, and this group was sister to G. curviphylla and G. asterocalyx Diels (Fig. 3).

Discussion.

In his book “Gentians of the World,” Dr. Yong-Ming Yuan described a new Gentiana species named G. daofuensis (Yuan 2024); however, that work did not provide direct morphological or genetic evidence, nor did it designate type material. Based on field observations and specimen comparisons of G. daofuensis and its close relatives, our results clearly demonstrate that G. daofuensis differs from G. crassuloides in corolla color, calyx length, and habitat preference and from G. curviphylla in leaf shape and corolla color (Table 1; Fig. 2). Consequently, these three species can be reliably distinguished despite their sympatric occurrence in western Sichuan Province. Phylogenetic analysis incorporating multiple individuals of the target species placed G. daofuensis in a distinct, fully supported position in the molecular phylogenetic tree, confirming its status as a separate species in section Chondrophyllae s. l. Based on its morphological traits, G. daofuensis belongs to ser. Orbiculatae, which is characterized by ovate calyx lobes with a narrowed base.

Additional specimens examined (paratypes).

Gentiana daofuensis. China • Sichuan: Daofu County, near Taining Village, alt. 3650 m, 101.54°N, 30.54°E, 23 Jul 2025, flowering and with few fruits, P. C. Fu & S. S. Sun Fu 2025068 (HNWP 392647!; herbarium of Luoyang Normal University); • Daofu County, near Geka Village, alt. 3810 m, 101.31°N, 30.78°E, 12 Sept 2023, in flower and fruit, Y. M. Yuan Fu 2023089 (herbarium of Luoyang Normal University).