Didymocarpus pingyuanensis Ling H. Yang, Q. Fan & F. Wen, 2024

Yang, Ling-Han, Dai, Jing-Min, Wen, Fang, Liu, Jian-Hui, Lan, Xue-Zheng & Fan, Qiang, 2024, Didymocarpus pingyuanensis (Gesneriaceae), a new species endemic to Danxia landscape from Guangdong Province, China, and two new combinations in Didymocarpus, PhytoKeys 244, pp. 213-224 : 213-224

Didymocarpus pingyuanensis Ling H. Yang, Q. Fan & F. Wen sp. nov.

Figs 3 , 4

Diagnosis.

Didymocarpus pingyuanensis is similar to D. heucherifolius var. gamosepalus and D. salviiflorus in having a similar zygomorphic corolla and pink to pinkish-purple funnel-shaped to tubular corolla tube, but can be distinguished from D. heucherifolius var. gamosepalus by its corolla size 1.8–3.8 cm long (vs. 3.6–4.3 cm long), calyx deeply 5 - lobed to about three quarters of the calyx length, apex rounded, rarely cuspidate, overlapping at margin (vs. 5 – lobed from middle to above middle); from D. salviiflorus , it differs by having calyx 5 - lobed to about three quarters of the calyx length (vs. 5 - lobed to about half of the calyx length from the base), bracts free, elliptic (vs. bracts free to connate, semiorbicular), and corolla glabrous outside (vs. puberulent outside).

Type.

China. Guangdong Province: Meizhou City, Pingyuan Town , 24 ° 32 ' N, 115 ° 50 ' E, 491 m a. s. l., 1 April 2023 (fl.), Qiang Fa, Xing-yue Zhang, Li-juan Liao, Jie-hao Jin, Ling-han Yang DNPC 3352 (holotype: SYS!; isotypes: IBK! IBSC! SYS!)

Description.

Acaulescent perennial herb. Rhizome horizontal, 2–4 cm long, ca. 1 cm in diameter. Leaves 4–9 basal, clustered at the apex of the rhizome, whorled; leaf blades chartaceous, orbicular-ovate to triangular, 4–11 cm long, 4.5–12 cm wide, apex slightly acute, base cordate, margin lobed (lobes 18–21, irregularly triangular, with irregular teeth), upper surface densely cover with white pilose hairs, green, lower surface with sparsely short hairs and pilose brown hairs confined to the veins, pale green, basal veins 5, palmate; petiole terete, pale green, 2.5–9 cm long, densely covered with pilose brown hairs, Cymes axillary, usually 3–6 on a stem, pseudodichotomous, scapiform, each 2 - to numerous flowered; Peduncle 10–18 cm long, covered with white dense short hairs and sparsely pilose brown hairs; Bracts free, elliptic, 5–12 mm long, serrate, long ciliate; Pedicel up to ca. 2.5 cm long, with short hairs; Calyx deeply 5 - lobed to about three quarters of the calyx length, lobes equal, obovate, apex rounded, rarely cuspidate, overlapping at margin, 6–9 mm long, 4.5–6 mm wide at the widest part and 2–3 mm wide at the base, lobes margin denticulate, puberulent outside, glabrous inside. Corolla zygomorphic, pink to magenta, up to ca. 3.8 cm long; glabrous outside, inside with glandular puberulent hairs from the throat to the corolla base and two wide bright yellow strips at the throat; tube funnel-shaped to tubular, 1.2–2.3 cm long, ca. 6.5 mm in diameter at base, ca. 1.1 cm in diameter at throat; limb distinctly 2 – lipped, adaxial lip 2 - lobed to near middle, 0.6–1 × ca. 1.3 cm, obliquely triangular, abaxial lip 3 - lobed to base, lobes rounded or oblong, ca. 0.9 × 1.6 cm, more or less equal. Stamens 2, adnate to corolla ca. 2 cm above the base of the corolla tube; filaments white, 8–13 mm long, slightly geniculate above base, swollen at middle, glabrous with glandules on the surface; anthers pale yellow, ca. 3 mm long, cohering face to face, white woolly. Staminodes 3, adnate to 1.5–4 mm above the base of the corolla tube, 0.4–0.8 mm long, white, glabrous. Pistil 2.2–3 cm long, puberulent; ovary white, cylindrical, puberulent; style ca. 2.3 mm long; stigma 1, cephaloid, centrally sunken, undivided, translucent. Capsule purplish-red when young, linear-cylindrical, glandular puberulent, up to ca. 9 cm long.

Phenology.

The flowering of Didymocarpus pingyuanensis is from April to May; and the fruiting is in June.

Distribution and habitat.

Didymocarpus pingyuanensis so far has only been found on three Danxia landscapes within Pingyuan County. It is locally abundant and endemic to a narrow area near the type locality. This species prefers moist, but sunny cliffs, at an elevation of 100–500 m a. s. l. In Pingyuan, the average temperature is 21.7 ° C, and the average annual precipitation is 1637 mm.

Etymology.

The specific epithet refers to the type locality, Pingyuan County, Guangdong Province, China. The Chinese name of the new species is here given as 平远长蒴苣苔 (Píng Yuǎn Cháng Shuò Jù Tái).

Additional specimens examined.

Didymocarpus pingyuanensis (paratypes): China, Guangdong, Pingyuan: Nantai Mountain , 24 ° 33 ' N, 115 ° 53 ' E, 168 m a. s. l., 6 May 2023, Qiang Fan, Zheng-Fei Li, Ling-Han Yang 20212 ( SYS) ; Nantai Mountain , 24 ° 32 ' N, 115 ° 50 ' E, 491 m a. s. l., 7 May 2023, Qiang Fan, Zheng-Fei Li, Ling-Han Yang 20219 ( SYS) ; Dahebei scenic spot , 24 ° 36 ' N, 115 ° 49 ' E, 300 m a. s. l., 7 May 2023, Qiang Fan, Zheng-Fei Li, Ling-Han Yang 20221 ( SYS) .

Didymocarpus heucherifolius : China, mountains between Shicheng in southeastern Jiangxi and Ninghua in western Fujian, 1200 m a. s. l., 7 May 1921, Te-Hui Wang ( IBSC 0005130 , isotype) .

Didymocarpus salviiflorus : China, Zhejiang, Lishui, 19 April 1930, Guan-Guang Zhong ( 00030758 , isotype) .

Didymocarpus heucherifolius var. yinzhengii : China, Hunan, Yongxing , 26 ° 2 ' 28 ″ N, 113 ° 9 ' 8 ″ E, 140 m a. s. l., 13 May 2023, Qiang Fan, Zheng-Fei Li, Ling-Han Yang 20265 ( SYS) .

Figures

Figure 3. Didymocarpus pingyuanensis A habitat in flowering B adaxial surface view of leaf blade C abaxial surface view of leaf blade D capsule E front view of corolla F lateral view of corolla, showing calyx deeply 5 - lobed to about a quarter of the calyx length from the base G bracts H opened corolla I staminodes J pistil K stamens (Photographers: A – K by Qiang Fan).

Figure 4. Didymocarpus pingyuanensis Ling H. Yang, Q. Fan & F. Wen A habit B flower in front view C flower in lateral view D opened corolla, showing stamens and staminodes E stamens F pistil and stigma (Drawn by Rong-En Wu).