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| Isotrema sanyaense R.T.Li, X.X.Zhu & Z.W.Wang
in Li, Wang, Wang, et al., 2019.
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Abstract
Isotrema sanyaense R.T.Li, X.X.Zhu & Z.W.Wang, sp. nov., a new species from Hainan island, China, is described and illustrated here. It is morphologically most similar to I. ledongense (Han Xu, Y.D.Li & H.J.Yang) X.X.Zhu, S.Liao & J.S.Ma and I. jianfenglingense (Han Xu, Y.D.Li & H.Q.Chen) X.X.Zhu, S.Liao & J.S.Ma in the shape of leaf, flower, and the yellow to brown villous indumentum of the pedicel, ovary and calyx. However, I. sanyaense can be easily distinguished from the latter two species by its 1–5-flowered cymes, in hanging clusters of 1 to numerous branches, upper calyx tube obviously longer than basal calyx tube, calyx limb discoid, yellow inside, with purple-red stripes and spots, about 13–18 mm in diameter, glabrous, and a throat dark red without spots, 4–6 mm wide.
Keywords: Aristolochia, Aristolochia subgenus Siphisia, Asia, morphology, taxonomy
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| Figure 2. Isotrema sanyaense R.T.Li, X.X.Zhu & Z.W.Wang, sp. nov. A habit B leaves (adaxially and abaxially) C inflorescence D flower (lateral view) E opened flower (showing the inside structure) F anthers and gynostemium G fruit H seeds.
Scale bars: 1 cm (B, C); 2 cm (D, E, G); 5 mm (F, H).
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Isotrema sanyaense R.T.Li, X.X.Zhu & Z.W.Wang, sp. nov.
Diagnosis: Isotrema sanyaense is most similar to I. ledongense (Han Xu, Y.D.Li & H.J.Yang) X.X.Zhu, S.Liao & J.S.Ma and I. jianfenglingense (Han Xu, Y.D.Li & H.Q.Chen) X.X.Zhu, S.Liao & J.S.Ma (Zhu et al. 2019), but significantly differs in the following characters: cymes 1–5-flowered, in hanging clusters of 1 to numerous branches, the pedicel nearly equal in length to flower, upper calyx tube obviously longer than basal calyx tube, calyx limb discoid, yellow inside, with purple-red stripes and spots, about 13–18 mm in diameter, glabrous, the throat dark red without spots, 4–6 mm wide. A detailed morphological comparison among the three species is shown in Figure 4 and Table 1.
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Etymology: The specific epithet is derived from the type locality, Sanya City, in Hainan island, China. The Chinese name is given as “三亚关木通”.
Distribution and habitat: Isotrema sanyaense is currently known from Haitangwan Town, Haitang District, Sanya City, Hainan Province, China. It grows in lowland dry forests dominated by families including Euphorbiaceae, Fagaceae, Lauraceae, Myrtaceae, Arecaceae and Rubiaceae at elevations between 332–400 m.
Rongtao Li, Zhiwei Wang, Jun Wang, Xinxin Zhu and Han Xu. 2019. Isotrema sanyaense, A New Species of Aristolochiaceae from Hainan, China. PhytoKeys. 128: 85-96. DOI: 10.3897/phytokeys.128.35042
