Tuesday, January 30, 2018

[Botany • 2018] Aristolochia sinoburmanica • A New Species (Aristolochiaceae) from north Myanmar


Aristolochia sinoburmanica Y.H.Tan & B.Yang

in Yang, Ding, Zhou, Zhu, Li, Maw & Tan, 2018

Abstract
Aristolochia sinoburmanica Y.H.Tan & B.Yang, a new species of Aristolochiaceae from Putao, Kachin State, Myanmar, is described and illustrated. According to morphology (strongly curved perianth, 3-lobed limb, as well as 3-lobed gynostemium, anthers 6, adnate in 3 pairs to the base of gynostemium, opposite to the lobes), the species belongs to Aristolochia subgenus Siphisia. It is morphologically similar to A. faviogonzalezii, A. hainanensis, A. tonkinensis, A. saccata and A. xuanlienensis. The major differences between them are outlined and discussed. A detailed description, along with line drawings, photographs, habitat, distribution and conservation status, as well as a comparison to morphologically similar species, are also provided.

Keywords: Kachin state, Aristolochia, Aristolochiaceae, field expedition, Myanmar



Figure 2. Aristolochia sinoburmanica  Y.H.Tan & B.Yang, sp. nov.
 A young branch and adaxial leaf B young branch and abaxial leaf C cymes on old woody stems D front view of preanthesis flower E front view of open flower F lateral view of open flower G lateral view of young flower H longitudinal section of flower I gynostemium, ovary and pedicel. (Photographed by Y. H. Tan, H. B. Ding & B. Yang). 

Aristolochia sinoburmanica Y.H.Tan & B.Yang, sp. nov.

Diagnosis: Aristolochia sinoburmanica is morphologically similar to A. hainanensis Merrill, A. saccata Wallich, A. xuanlienensis (Huong et al. 2014), A. faviogonzalezii T. V. Do, S. Wanke & C. Neinhuis and A. tonkinensis T.V. Do & S. Wanke from Vietnam (Do et al. 2015a), but is distinguishable from these species by the following diagnostic characters: leaf blade ovate or ovate-lanceolate to narrowly ovate, subcoriaceous, base rounded to slightly cordate; cyme solitary on old woody stems and young branches, each cyme with 1–2 flowers; perianth claret (deep purple red), outside densely brown hirsute with parallel dark purple veins, 6.5–7.5 cm high; tube horseshoe-shaped, 8.3–8.5 cm, uniformly claret (deep purple red), with visible dark purple veins, limb trumpet-shaped, 4.2–4.8 cm high, 4–4.4 cm wide, 3-lobed, lobes subequal; throat deep purple red, glabrous.


Etymology: The species epithet refers to the type locality in Myanmar and adjacent regions of China. It also shows that the two countries are friendly neighbours, their friendship being retained over a long period and also expresses our appreciation for the whole-hearted cooperation amongst members of the China-Myanmar joint expedition.

Distribution and habitat: Aristolochia sinoburmanica is hitherto known from the type locality of Putao, Kachin state in north Myanmar and adjacent regions of Gongshan County, northwest Yunnan, southwest China, where, according to one sheet of the specimen deposited in KUN, it is a perennial liana which grows under the montane broadleaf forests, at an elevation of ca. 900–1400 m.


Discussion: Aristolochia sinoburmanica is morphologically similar to A. faviogonzalezii, A. hainanensis, A. tonkinensis, A. saccata and A. xuanlienensis. However, the new species differs from the aforementioned species in several important vegetative and reproductive characters (summarised in Table 1). A. sinoburmanica, with a horseshoe-shaped perianth of 3 lobes which are valvate in preanthesis, annulated perianth throat and gynostemium with trilobed stigma on top, each lobe consisting of one pair of stamens, belongs to the Aristolochia subgenus Siphisia (Wanke et al. 2006, Do et al. 2015a).This new discovery, along with several new species recently described from Vietnam (Huong et al. 2014, Do et al. 2014, 2015a, 2015b), Guangxi and Hainan Island, China (Xu et al. 2011, Huang et al. 2013, Wu et al. 2013) and Peninsular Malaysia (Yao 2012), provide evidence that the genus Aristolochia and, in particular, Aristolochia subgenus Siphisia is very diverse in South-East Asia. Currently there are only 12 Aristolochia species recorded in Myanmar (Kress et al. 2003), indicating that the species diversity of Aristolochia in Myanmar is still open to discovery. It is predicted that more new species will be discovered when more field investigations are conducted in this region.


Bin Yang, Hong-Bo Ding, Shi-Shun Zhou, Xinxin Zhu, Ren Li, Mya Bhone Maw and Yun-Hong Tan. 2018. Aristolochia sinoburmanica (Aristolochiaceae), A New Species from north Myanmar. PhytoKeys. 94: 13-22.  DOI: 10.3897/phytokeys.94.21557


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