Oreocharis chenzhouensis X. L. Yu, R. H. Tu & A. Liu, 2023

Zhou, Guo-Hui, Tu, Rong-Hui, Liu, Ang & Yu, Xun-Lin, 2023, Oreocharis chenzhouensis, a new species of Gesneriaceae from southern Hunan, China, Phytotaxa 607 (3), pp. 197-204 : 197-201

Oreocharis chenzhouensis X. L. Yu, R. H. Tu & A. Liu , sp. nov. ( Figs. 1–3 )

Diagnosis:— In terms of reproductive organs, the new species is similar to O. burtii , but mainly differs by its abaxial leaf surface being densely fulvous pannose and abaxially glabrous corolla tube. The new species is also similar to O. sinohenryi ( Chun 1946: 290) Mich. Möller & A. Weber in Möller et al. (2011: 26) in leaves, but differs by its purple corolla and the longer peduncle. In addition, their distributions are also allopatric ( Fig. 4 ).

Type: — CHINA. Hunan Province: Chenzhou City, Yizhang County, Huixi Village , 25°37′6.36″N, 113°10′53.91″E, on the moist rock in granite area, primarily in the lower part of mountains, elevation ca. 610 m, 21 October 2017, Rong-Hui Tu & Yao-Nan Yin 17092101 (holotype, CSFI!, isotypes, CSFI!, CSH!& HIB!) .

Perennial herbs, creeping, rhizomes conspicuous, stem densely fulvous pannose, up to 10 cm long. Leaves clustered at the top of the rhizome, alternate on the stem or the offshoots; petiole 3–7 cm long, densely fulvous pannose; leaf blade thickly papyraceous, obovate-oblong, 6–15 × 1.5–5 cm, adaxially densely pubescent, abaxially densely fulvous pannose, base cuneate, usually asymmetric, margin crenate, apex obtuse; lateral veins 9–13 pairs, adaxially impressed, abaxially with veinlets strongly raised. Cymes 5–10, axillary, 2–4 branched, 5–15—flowered; peduncles 14–18 cm long, densely fulvous woolly, tapering upwards; bracts 2, opposite, subulate, 3–6 × 0.6–1.2 mm long, appressedpubescent, margin densely woolly. Pedicels 1.5–2.5 cm long, sparsely tomentose. Calyx 5-parted close to the base, segments narrowly triangular, 2–3 × 0.5–1 mm, outside densely woolly, inside puberulent. Corolla purple, ca. 2 cm long; tube narrow-tubular, 12–15 × 3–5 mm, glabrous, bent above the middle, ca. 3.5 mm in diameter at the mouth, throat densely glandular-pubescent; limb distinctly 2-lipped; adaxial lip 2-lobed, lobes 3–5 mm long, abaxial lip 3- lobed, lobes obovate-elliptic to suborbicular, 5–6 mm long, margin with glandular hairs. Stamens 2, adnate to ca. 3 mm above the base of the corolla tube, filaments ca. 7 mm long, linear, glabrous; staminode 1 or absent, ca. 2 mm long, adnate to ca. 3 mm above the base of corolla tube. Disc ring-like, ca. 1 mm high, with entire margin. Pistil ca. 8 mm long, glabrous, ovary ca. 5 × 1 mm, glabrous, style ca. 3 mm long, terete and glabrous; stigmas 2-lobed, ca. 1 mm long, elliptic and glabrous. Capsule linear, gradually widening from the base to the middle, widest at the middle, then gradually tapering from the middle to the apex, 2.4–3.2 cm long, ca. 2 mm in diam. at the middle, glabrous.

Distribution and habitat: — Oreocharis chenzhouensis is only distributed at its type locality: Shizikou Mountain, Chenzhou City, Hunan Province, China. It grows on moist rocks in the lower part of the mountain at an elevation from 240 m to 680 m. It is a typical drought-enduring plant, which becomes withered when lacking water but can revive again when receiving water ( Fig. 2A–B ).

Conservation status: — Oreocharis chenzhouensis was only found from its type locality with six populations ( Fig. 4 ). Each O. chenzhouensis population comprises about 300 mature individuals. The habitat is not located in any protected area, nature reserve or park, and no protective measures have been taken. However, the habitat has not been over-developed, nor greatly disturbed by human activities. The number of population has not changed obviously in the past few years. Therefore, according to the IUCN Red List Criteria ( IUCN 2022), O. chenzhouensis should be considered as “Vulnerable, VU B2ab(v) + C2a(ii)”.

Phenology: —Flowering from August to September; fruiting from August to October.

Etymology: —The epithet of this new species is derived from the type locality, Chenzhou City.

Similar species: — Oreocharis chenzhouensis is morphologically similar to O. burtii and O. sinohenryi . It mainly differs from O. burtii by its abaxial leaf surface being densely fulvous pannose (vs. densely appressed puberulous), peduncle 14–18 cm long (vs. 4–10 cm long), staminode 1 or absent (vs. staminode absent), abaxially glabrous (vs. densely puberulent) corolla tube. It also differs from O. sinohenryi by its narrowly triangular calyx lobes (vs. lanceolate calyx lobes), purple corolla colour (vs. orange to orange-red corolla colour) and peduncle 14–18 cm long (vs. 6–10 cm long). A detailed morphological comparison of the three species is shown in Table 1 and Figure 5 .

Figures

FIGURE 1. Oreocharis chenzhouensis. A. Plant with flowers and capsules. B. Front view of flower. C. Side view of flower. D. Bottom view of flower. E. Opened corolla showing two stamens and one staminode. F. Pistils. G. Capsule. H. Calyx segments. I. Cross section of leaf blade. Drawn by Jing Tian.

FIGURE 2. Oreocharis chenzhouensis. A and B. Habitat. C. Habit. D. Inflorescence. E. Adaxial leaf surface. F. Flower in front view. G. Flower in side view. H. Mature capsules. I. Abaxial leaf surface. J. Opened corolla showing two stamens and pistil. K. Opened corolla showing two stamens, one staminode and pistil. L. Immature capsule. Photographed by Rong-Hui Tu.

FIGURE 3. Holotype of Oreocharis chenzhouensis (Rong-Hui Tu & Yao-Nan Yin 17092101, CSFI).

FIGURE 4. Geographic distribution of Oreocharis chenzhouensis and its related taxa in China.

FIGURE 5. Oreocharis chenzhouensis (A1–A5), O. burtii (B1–B5) and O. sinohenryi (C1–C5). A1, B1 and C1. Plant habit; A2, B2 and C2. Flower in front view; A3, B3 and C3. Flower in side view; A4, B4 and C4. Fruits; A5, B5 and C5. Abaxial surface of leaf. A1–A5 photographed by Rong-Hui Tu; the others photographed by Peng-Wei Li.