Research Article |
Corresponding author: Yi-Hua Tong ( yh-tong@scbg.ac.cn ) Academic editor: Hugo de Boer
© 2022 Chun-Mei He, Xin-Xin Zhou, Xue-He Ye, Weijun Chen, Yi-Hua Tong.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
He C-M, Zhou X-X, Ye X-H, Chen W, Tong Y-H (2022) Erythroxylum austro-guangdongense (Erythroxylaceae), a new species from Guangdong, China. PhytoKeys 202: 133-138. https://doi.org/10.3897/phytokeys.202.84688
|
Erythroxylum austroguangdongense (Erythroxylaceae), a new species from Guangdong Province, China, is described and illustrated. This new species is morphologically most similar to E. calyptratum, but is distinguished by the leathery leaf blade with fewer pairs of secondary veins and flowers borne on leafless nodes of the basal part of the current branch with much longer pedicels and sub-rectangular petal appendages. This is the second native species of Erythroxylum recorded from China.
Coca family, morphology, taxonomy
The genus Erythroxylum P. Browne (Erythroxylaceae), with about 264 species, is widely distributed in tropics and subtropics with the center of its diversity in Neotropics (
During field surveys of medicinal plant resources in Guangdong Province, we encountered an unknown Erythroxylum species with white flowers, while the species previously recorded from China either has whitish-yellow (E. novogranatense) or pinkish (E. sinense) flowers. After a morphological comparison with specimens in the herbarium (IBSC) and consulting the relevant literature (e.g.
Flowering and fruiting material was collected from Zhuhai and Taishan, Guangdong Province, China during several field trips from 2019 to 2022. Descriptions were based on both living and dried collections, which were deposited at the herbarium of South China Botanical Garden, Chinese Academy of Sciences (
China. Guangdong Province: Taishan, Chaliao Ao, 22°12'54.87"N, 112°57'34.84"E, 563 m a.s.l., 3 April 2021 (fl.), Xin-Xin Zhou & Yue-Yao Liu LSX303 (holotype:
Most similar to E. calyptratum Komada & Tagane in having reddish brown to grayish brown branches with dense lenticels, and white petals with appendages, but distinguished by the leathery (vs. thinly chartaceous) leaf blade with fewer pairs of secondary veins (6–8 pairs vs. 11–15 pairs), and flowers borne on leafless nodes of the basal part of current branch (vs. in leaf axils) with longer pedicels (1–1.5 cm vs. 5.2–7 mm) and sub-rectangular petal appendage (vs. bilobed appendage with each lobe consisting of a short anterior auricle and a large posterior auricle). A more detailed comparison of the two species is shown in Table
Morphological comparison of Erythroxylum austroguangdongense and E. calyptratum.
Characters | E. austroguangdongense | E. calyptratum |
---|---|---|
Leaf blade texture | Leathery | Thinly chartaceous |
Leaf blade shape | Elliptic or lanceolate | Elliptic, oblong, oblong-lanceolate or ovate |
Leaf blade color | Dark green and shining adaxially | Pale green adaxially |
Secondary veins | 6–8 pairs | 11–15 pairs |
Flower | Solitary on leafless nodes of the basal part of current branch | Solitary to 3-fascicled in leaf axils |
Pedicel length | 1–1.5 cm | 5.2–7 mm |
Petal appendage | Sub-rectangular | Bilobed and each lobe consisting of a short anterior auricle and a large posterior auricle |
Erythroxylum austroguangdongense A flowering branches B leafy branches C female flowers D male flower E stipule, showing fimbriate margin F flower bud, showing calyx G petals, adaxial (left), lateral (middle) and abaxial (right) view H androecium I staminodes and pistil J cross section of ovary, showing one fertile locule (low right) K–L fruits. Scale bars: 3 mm (H); 2 mm (E–G, I); 1 mm (J). Photographs A–B by Xin-Xin Zhou D, K by Wei-Jun Chen H by Xue-He Ye and others by Chun-Mei He.
Shrubs deciduous, 1.5–2 m tall, dioecious. Young branches greenish, old branches reddish-brown to grayish-brown, lenticellate. Stipule triangular to narrowly triangular, 1.8–3 × 0.7–0.8 mm, margin entire when young, gradually fimbriate, or dissected, caducous when old. Leaves alternate, simple; petiole 3.5–6 mm long; blade elliptic or lanceolate, 4–7.7 × 1.6–2.5 cm, leathery, apex acuminate, acumen to 5 mm long, base cuneate or attenuate, margin entire, dark green and shining adaxially, pale green abaxially, midrib sunken adaxially, prominent and pale yellow to brownish-yellow abaxially, secondary veins 6–8 pairs, almost flat, faintly visible on both surfaces, tertiary veins reticulate, obscure adaxially, slightly visible abaxially. Flowers solitary on leafless nodes of the basal part of current branch, pedicel 1–1.5 cm long; bracteole triangular, ca. 0.8 mm long, margin fimbriate or serrately dissected; calyx 1.6–1.8 mm long, lobes 5, ovate-triangular, ca. 1 mm long, apex brownish, acute; petals 5, white, oblong, 3.7–4 mm long, apex obtuse or rounded, adaxially with one appendage attached ca. 1.5 mm above from base, appendage sub-rectangular, ca. 1.6 × 1 mm, papillate throughout, slightly concave on both upper and lower margin. Stamens or staminodes 10. Male flowers: stamens with different length of filaments arranged alternately, short filaments ca. 3.7 mm long, long ones ca. 4 mm long, all basally connate into a tube, tube ca. 2 mm long, densely covered with papillary trichomes; anthers ca. 1.1 mm long; sterile pistil ca. 4 mm long. Female flowers: staminodes ca. 1.2 mm long, staminodal tube ca. 1 mm long, anther absent; ovary ellipsoidal, 2–2.5 mm long, 1–1.3 mm in diam., 3-locular, with 1 fertile locule, styles 3, entirely free at base, ca. 1 mm long including stigma, stigma clavate, ca. 0.5 mm long, reflexed, with papillae. Young fruits green, turning to yellowish, ripening red, ovoid to reniform, apex oblique, 7–9 × 2.5–3 mm.
The species epithet is named after the distribution area of this new species, South Guangdong.
南粤古柯 (Chinese pinyin: nán yuè gŭ kē).
This species is currently known only from Guangdong Province, China. Three populations are found in Yangchun (E’huangzhang), Zhuhai (Fenghuang Mountain) and Taishan (Gudou Mountain) respectively. It grows in evergreen broadleaved forests at elevations of 170–800 m.
According to the field observation, the number of mature individuals of Erythroxylum austroguangdongense is less than 100. Thus, it is assigned a status of ‘Endangered’ (EN) following the IUCN Red List categories and criteria (
Flowering in March-April and fruiting in April-August.
China. Guangdong, Taishan: Banyuzui, 448 m a.s.l., 28 March 2019 (fl.), Lei Jiang, Jin-Fan Lin, Jin-Ye Feng, Fu-Jun Chen & Jie-Lin Chen GDS-00291 (
This new species is the second native species reported from China, and it differs from previously recorded species, i.e., Erythroxylum sinense, in having leathery (vs. chartaceous) leaf blades with faintly visible (vs. prominent) veins and white (vs. pinkish) petals with sub-rectangular (vs. ligule-like) appendages.
Erythroxylum species, especially E. coca Lam. and E. novogranatense, are well known for their tropane alkaloids, such as cocaine (
We are grateful to Mr. Feng Ling and Mr. Yue-Yao Liu for their help during field trips. Our thanks also go to the curators of