Aristolochia sinoburmanica (Aristolochiaceae), a new species from north Myanmar

Aristolochia sinoburmanica (Aristolochiaceae), a new species from northern Myanmar, were published on special issue of PhytoKeys.

Aristolochia L., with about 550 recognized species, is a predominantly tropical and subtropical genus that extends to the Mediterranean and temperate zones worldwide and has highest species richness in the New World. The genus is also rich in Asia, particularly in eastern and southern Asia, with more than 70 species. There are currently 61 species recorded in China, 22 species in Vietnam and 12 species in Myanmar. Recent phylogenetic studies of the genus based on morphological and molecular data suggested the subdivision of Aristolochia into three subgenera, i.e. subgenus Aristolochia, subgenus Siphisia and subgenus Pararistolochia

During a field expedition to Putao, Kachin state, north Myanmar, an unknown species of Aristolochia was collected. After careful studies of the genus, particularly the floral characteristics of those species in the adjacent regions, as well as comparison between this unknown species and its related species, it is confirmed as a new species of Aristolochia which has strongly curved perianth, 3-lobed limb, as well as 3-lobed gynostemium and should be assigned to the subgenus Siphisia. The new species presented here was also collected by a famous Chinese botanist, Professor K. M. Feng in 1959 (KUN, No. 0163232) from northwest Yunnan, China.

The species epithet refers to the type locality in Myanmar and adjacent regions of China. It also shows that the two countries are friendly neighbors, 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.

Aristolochia sinoburmanica is morphologically similar to A. hainanensis, A. saccata, A. xuanlienensis, A. faviogonzalezii and A. tonkinensis from Vietnam, 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.

This work was financially supported by a project of the Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences (Y4ZK111B01).The result published as "Aristolochia sinoburmanica (Aristolochiaceae), a new species from north Myanmar " on PhytoKeys.

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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).