Monday, November 12, 2018

[Botany • 2018] Henckelia pathakii (Gesneriaceae) • A New Species of Henckelia from Arunachal Pradesh, India


Henckelia pathakii G. Krishna & Lakshmin. 

in Krishna & Lakshminarasimhan, 2018. 
Photographed by Gopal Krishna

Abstract
Henckelia pathakii G. Krishna & Lakshmin. sp. nov., is described and illustrated here from Upper Siang district of Arunachal Pradesh, India. It differs from its closely related species H. adenocalyx and H. grandifolia in having cupular bracts (vs. free and slightly connate at base) and glabrous (vs. densely hairy or sparsely pubescent), eglandular calyx. As it is narrowly confined to Upper Siang district of Arunachal Pradesh in a small population comprising about 20 individuals in a single location. The threat status of this new species is provisionally assessed here as “Critically Endangered” following the IUCN Red List Categories and Criteria version 3.1 (2012).

Keyword: Arunachal Pradesh, Gesneriaceae, Henckelia pathakii, India


Fig. 1. Henckelia pathakii G. Krishna & Lakshmin. sp. nov. (A) Flowering twig, (B) Inflorescence with cupular bract, (C) Corolla split open (showing stamens and staminodes), (D) Calyx splitted, (E) Pistil with disk
[Drawn by Dineshwar Kumar Sah, (A–E) 
from holotype M.K. Pathak & Gopal Krishna 134270]

Fig. 2. Henckelia pathakii G. Krishna & Lakshmin. sp. nov. (A) Habit, (B) Solitary flower with cupular bract, (C) Inflorescence with cupular bract, (D) Corolla front view (stigma visible) [Photographed by Gopal Krishna]

Henckelia pathakii G. Krishna & Lakshmin. sp. nov. 

The new species can easily be distinguished from H. adenocalyx in glabrous nature of calyx (vs. hairy outside and sessile glands often on both surfaces); corolla glabrous (vs. puberulous corolla), variegated, sparsely adaxially hairy to glabrescent, glabrous beneath except midvein and lateral veins (vs. non-variegated, hairy on both sides) and bracts 2, red-greenish, fused forming a cup, coriaceous, glabrous (vs. bracts 2, greenish, free or adnate at the base, chartaceous, hairy). It differs from its another closely related ally, H. grandifolia by having cupular, glabrous bracts and glabrous corolla (vs. externally pubescent corolla). Comparison of diagnostic characters between the allied species is provided in detail in Table 1. 
....

Etymology: The specific epithet is named in honour of late Dr. M.K. Pathak (Botanist), Botanical Survey of India, for his significant contribution to the Flora of Arunachal Pradesh, India, who passed away suddenly on 7 Feb. 2013. 

Distribution and habitat: Henckelia pathakii is known only from the type locality, Upper Siang district of Arunachal Pradesh, India growing at an elevation of 1980 m, on outcrops of shaded moist hillslopes in subtropical evergreen forests. (Fig. 3)


Gopal Krishna and Pakshirajan Lakshminarasimhan. 2018. A New Species of Henckelia (Gesneriaceae) from Arunachal Pradesh, India.  Taiwania. 63(4); 397-401. DOI: 10.6165/tai.2018.63.397