Thursday, September 15, 2022

[Botany • 2022] Aristolochia rethyae (Aristolochiaceae) • A New Species from Arunachal Pradesh, north-east India


Aristolochia rethyae S. Kashung, Rimi Barman et P. R. Gajurel, 

in Kashung, Gajurel, Singh, Barman et Yakang, 2022. 
 
Abstract
Aristolochia rethyae, a new species from Arunachal Pradesh, north-east India, is described. Aristolochia rethyae is affinis to A. griffithii and A. tanzawana with similar leaf texture and shallowly 3-lobed perianth limb, but differs from A. griffithii in its ovate to narrowly ovate leaf shape, cauliflorous flower borne in a cluster and densely hirsute brown capsule, and from A. tanzawana in their cauliflorous inflorescence, S-shaped perianth and capsule size with distinct wavy ridges.

Keywords: Arunachal Pradesh, Critically Endangered, India, new taxon, Siphisia, Magnoliids

 Aristolochia rethyae—A. Habit; B. A branch; C. Adaxial leaf surface; D. Abaxial leaf surface; E. Cymose inflorescence; F & G. Immature capsules; All photographed by Soyala Kashung;
 H. Isotype image of Aristolochia griffithii (GH00353571); I. Holotype image of Aristolochia tanzawana (KPM-NA1000103) provided by Kanagawa Prefectural Museum of Natural History, Japan; J. Holotype image of Aristolochia rethyae S. Kashung, Rimi Barman et P. R. Gajurel.

  Aristolochia rethyae—A. Flower in pre-anthesis; B. Frontal view of flower; C. Lateral view of flower; D. Longitudinal section of utricle showing the gynostemium; E. Tip of the gynostemium; F. Stamens on gynostemium; G. Cross section of gynostemium showing the stamen arrangement; H. Cross section of ovary; I. Hair on capsule.
 A–C photographed by Soyala Kashung; D–I photographed by Rimi Barman.

Aristolochia rethyae S. Kashung, Rimi Barman et P. R. Gajurel, sp. nov. 

 Aristolochia rethyae is morphologically close to A. griffithii and A. tanzawana (Kigawa) Watan.-Toma & OhiToma (2014:160) in its leaf texture which is densely pubescent abaxially, and the perianth limb being shallowly 3- lobed. However, it can be distinguished very easily from A. griffithii in its ovate to narrowly ovate leaves, cauliflorous inflorescence, pubescent perianth and capsule texture. It is also distinctly different from A. tanzawana in its cauliflorous inflorescence, S-shaped perianth and much larger capsule with distinct wavy ridges.

Etymology:— The specific epithet honors Dr. Parakkal Rethy, former Professor of Department of Forestry, North Eastern Regional Institute of Science and Technology, Arunachal Pradesh, India, for her contribution to the field of Angiosperm taxonomy.




 
Soyala Kashung, Padma Raj Gajurel, Binay Singh, Rimi Barman and Tage Yakang. 2022. Aristolochia rethyae, A New Species from Arunachal Pradesh, north-east India. Phytotaxa. 564(1); 1-7. DOI: 10.11646/phytotaxa.564.1.1