Sageretia ellipsoidea Yi Yang, H.Sun & H.Peng, 2021

Yang, Yi, Peng, Hua & Sun, Hang, 2021, Taxonomic revision of Sageretia (Rhamnaceae) from China I: identities of S. lucida, S. thea var. cordiformis and S. yunlongensis, with the description of a new species S. ellipsoidea, PhytoKeys 179, pp. 13-28 : 13

Sageretia ellipsoidea Yi Yang, H.Sun & H.Peng sp. nov.: tuo guo que mei teng (椭果雀梅藤) Figs 5 , 6 , 7

Type material.

China. Guangdong: "Ying Tak, Taai Tsan, Wan Tong Shan" (Yingde City, Taizhen Town, Wentang Mountain), 17 Oct 1926, W.T. Tsang & K.C. Wong 2718 (holotype IBSC [0404901]; isotype SYS [SYS00086833]); 18 Oct 1926, W.T. Tsang & K.C. Wong 2723 (paratype IBSC [0404896]); 6 Oct 1926, W.T. Tsang & K.C. Wong 2479 (paratype SYS [SYS00086832]).

Diagnosis.

Similar to S. hamosa (Wall.) Brongn., but differs in having smaller leaves (5-12 × 2.5-4 cm in S. ellipsoidea vs. 8-15 (-25) × 3.5-6 (-7) cm in S. hamosa ), less lateral veins (5-7 pairs vs. 7-11 pairs), shorter rachises (1-3 (-10) cm vs. 6-20 (-25) cm), and ellipsoidal or elliptic-ovoid fruits (vs. subglobose or globose in S. hamosa ).

Description.

Woody vines. Branches opposite or subopposite, glabrous; first-year branches green, sometimes with hard-straight spine opposite to leaf, second- to fourth-year branches reddish brown. Leaves opposite or subopposite; petioles 8-15 mm, leaf blades leathery, ovate-oblong, oblong to elliptic, 5-12 × 2.5-4 cm, lateral veins 5-7 pairs, prominent abaxially, impressed adaxially, base rounded, margin crenate, apex obtuse to shortly acuminate. Inflorescences usually axillary spicate, rarely spicate-paniculate; rachises 1-3 (-10) cm. Flowers subsessile, white to yellowish white; sepals triangular-ovate, ca. 1.5 mm, apex acute; petals clawed; stamens as long as petals. Drupes ellipsoidal or elliptic-ovoid, 10-12 × 5-7 mm, green, turning to orange-red, claret and finally purple-black, base with inconspicuous disk remains; pyrenes 1-2, emarginate at both ends, asymmetrical.

Phenology.

Flowering from April to July, ripe fruits from November to January of next-year.

Etymology.

This species is named for its ellipsoidal or elliptic-ovoid drupes which are different from other Sageretia species (subglobose or globose).

Distribution and habitat.

The species is currently found in southern China (Fujian, Guangdong, Guangxi, Hainan; Fig. 2 ), and probably in northeastern Vietnam. It grows in moist forests along streams on granite mountains below 1200 m.

Note.

When he erected the species Sageretia lucida , Merrill (1931) cited four collections, including W.T. Tsang & K.C. Wong 14340, 14579, 14584 and 15121, of which 15121 was selected as type and the other three collections were automatically treated as paratypes. However, the four numbers above belong to herbarium numbers which are ineffective nowadays, and the corresponding field numbers are W.T. Tsang & K.C. Wong 2479, 2718, 2723 and 3260, respectively. Moreover, another problem is that the paratype collections (2479, 2718 and 2723) factually represent an undescribed Sageretia species distinctly differing from S. lucida (3260) based on geological and morphological evidences. Among the four collections of S. lucida , three paratype collections were all collected from "Wan Tong Shan" (Wentang Shan) and type collection from "Chung Tung" (Zhongdong Village, about 10 km apart to the Wentang Shan). Based on field investigations, we find that Wentang Shan has granite landform while Zhongdong Village limestone landform. Furthermore, the three paratype collections are morphologically identical, but noticeably different from the type collection in terms of branchlet color (reddish brown in paratype collections vs. gray to dark gray in type collection), phyllotaxis (opposite or subopposite vs. alternate), rachis length (1-3 (-10) cm vs. 5-10 cm), and phenology (blooming in spring or early summer vs. in autumn) (seen in Table 2 ). Consequently, the species represented by the paratype collections of S. lucida is erected as a new species, namely S. ellipsoidea Yi Yang, H.Sun & H.Peng.

Besides, the samples of " Sageretia lucida " in Yang et al. (2019) factually also belong to S. ellipsoidea . According to Yang et al. (2019), the new species is sister to S. hamosa and they form an early diverging clade. In morphology and phenology, the new species also most resembles S. hamosa through sharing similar habit (woody vine), larger fruit size (ca. 1 cm long or in diam.) and fruiting season (winter). Nonetheless, S. ellipsoidea can be easily distinguished based on its smaller leaves, fewer lateral veins, shorter rachises, and ellipsoidal or elliptic-ovoid drupes (Table 2 ).

Additional specimens examined.

China. Fujian: Minhou County, 4 Oct 2014, B. Chen & D.M. Jin CSH12700 (CSH); Nanjing County, 400 m, 19 Nov 1963, Xiamen Univ. Coll. Team 805 (PE); Pinghe County , 600 m, 23 Feb 1980, G.S. He 0475 (FJSI); Zhao'an County , 950 m, 16 Mar 2015, X.F. Zeng ZXF19893 (CZH) . Guangxi: Jinxiu Yao Autonomous County, 200 m, 6 Apr 1982, Dayao Shan Expedition Team 13973 (IBSC); Shangsi County, Shiwandashan , 370-390 m, 14 Nov 2011, D.X. Nong et al. FC2011061 (GXMG) . Guangdong: Dinghu District, 8 Nov 1963, G.Q. Ding & G.L. Shi 1132 (IBSC); Fengkai County, 15 Nov 1980, G.Q. Ding & G.L. Shi 6652 (CDBI); Ruyuan Yao Autonomous County , 17 Aug 1935, S.K. Lau 23948 (IBK); Huaiji County , 500 m, 26 Oct 1958, Y.G. Liu 2707 (HHBG); Yangchun City, 6 Nov 1935, C. Wang 38672 (IBK, PE); Chao'an District , 900 m, 18 Oct 2009, X.F. Zeng ZXF8404 (CZH); Conghua District , 600 m, 4 Dec 1958, L. Deng 8836 (IBK); Shenzhen City, 300-350 m, 20 Sept 2006, G.D. Wang et al. 6474 (SZG); Boluo County , 444.6 m, 1 Apr 2019, Y. Yang OYY00121 (KUN) . Hainan: Baoting Li and Miao Autonomous County, 6 May 1935, F.C. How 72211 (IBK); Changjiang Li Autonomous County , 7 Jun 1934, H.Y. Liang 64162 (IBK); Baisha Li Autonomous County , 29 Apr 1936, S.K. Lau 26548 (IBK); Lingshui Li Autonomous County , 21 Oct 1956, L. Deng 2785 (KUN) .

Figures

Figure 2. Distribution of Rhamnus nigricans, Sageretia cordiformis, S. ellipsoidea, and S. lucida. The sites were obtained from the specimen records, our field investigations and photo information in CFH and PPBC.

Figure 5. Holotype of Sageretia ellipsoidea (IBSC [0404901]). Image obtained from CVH (https: // www. cvh. ac. cn /).

Figure 6. Field photos of Sageretia ellipsoidea A habit B branch C flowering branch D fruiting branch. A-C photographed by Y. Yang and D by J. Lin.

Figure 7. Sageretia ellipsoidea Yi Yang, H. Sun & H. Peng A flowering branch B fruiting branch C bottom surface of leaf blade D upper surface of leaf blade E drupe F pyrene (left) and seed (right).