Citrus × pubinervia D. G. Zhang & Z. H. Xiang, Y. Wu, 1753

Wu, Yu, Liu, Qun, Xiang, Zu-Heng & Zhang, Dai-Gui, 2021, Citrus × pubinervia, a new natural hybrid species from central China, Phytotaxa 523 (3), pp. 239-246 : 243-244

Citrus × pubinervia D. G. Zhang & Z. H. Xiang, Y. Wu , sp. nov. ( FIGURE 1, C 1 -4 & FIGURE 2 )

Type. CHINA. Hunan Province, Longshan County, Shuitianba Town, Feixiang Village , Bamboo forest, 29.527412° N, 109.598525° E, alt. 1055 m, 10 April 2019, D. G. Zhang 2019041001 (holotype: JIU !; isotype: HNU! ).

Description:—Evergreen treelets. Trunk green to brown. Young branches green, triangular, becoming cylindrical with age, usually with solitary spines at axils; spines 0.1–0.6 cm long, base flat, apex rufous. Leaves palmately 3-foliolate; petiole 1–2 cm, narrowly winged; leaflet leathery, margin finely crenulate, adaxially dark green, pilose along the main vein, abaxially yellow-green, glabrous, main vein obvious, lateral veins not obvious; central leaflet oval to ovate lanceolate, 12–25 × 49–73 mm, lateral leaflets 11–19 × 31–43 mm, base wide cuneate and asymmetric. Flowers hermaphrodite developed from branches of previous year, solitary or paired, pedicel 1–4 mm; calyx lobes 5, 2–3 × ca. 5 mm, apex serrulate, basally connate. Petals 5, imbricate, white or with purplish red slightly, obovate, 2–3 cm × 1.2–1.8 cm. Stamens 22–28; filaments 5–10 mm, pinkish and differing in length; anther yellow, with a protuberance at the top. Ovary 8–10-loculed, glabrous, near spherical; style short and thick; stigma depressions at the top. Fruits (hesperidium) prolate or obovoid, glabrous, dark yellow when matured, with sarcocarp segments of pulp vesicles. Seeds unknow.

Phenology. Flowering from May to June, fruiting from October to November.

Distribution and habitat. This new species is currently known from northwestern Hunan Province (Longshan County, Yongshun County, Shimen County, Yongding District) and southwestern Hubei Province (Changyang County; Chen 1993). It is usually distributed in the mountains at 900–1400 m and it is sometimes cultivated as a traditional medicine in these minority areas.

Vernacular name: ‡中ḝ, huá zhông zhǐ in Chinese Pinyin.

Etymology. The specific epithet “pubinervia” is derived from the pilose main vein of the new species.

Figures

FIGURE 1. Main morphological characters of C. × pubinervia and its related species: C. trifoliataA. Fruits, A. Leaves; C. × polytrifolia 1 2 B. Fruits, B. Leaves; C. × pubinervia. C. Fruits, C. Leaves, C. Anatomy of flowers, C. Flowering branch, C. Cross section of young 1 2 1 2 3 4 5 fruit.

FIGURE 2. Citrus × pubinervia D. G. Zhang & Z. H. Xiang, Y. Wu. A. Flowering branch, B. Stamens and pistil, C. A petal, D. Fruit and its cross section (drawing by Jianing Yang).