Sunday, November 27, 2022

[Botany • 2022] Lepidagathis decumbens (Acanthaceae) • A New Species from Tamil Nadu, India


 Lepidagathis decumbens N. Dhatchan. & S. Soosairaj,

in Dhatchanamoorthy, Karthikeyan, Raja, Soosairaj et Balachandran. 2022. 

Lepidagathis decumbens N. Dhatchan. & S. Soosairaj, sp. nov. is described and illustrated here from Eastern Ghats of Tamil Nadu, Southern India. This new species is closely allied to L. diffusa C.B. Clarke but differs by erect and decumbent habit, short internodes, long unilateral spikes, glandular sericeous floral parts, and ovoid seeds. Photographs of habit, spikes and flowers, pollen grains, seed SEM are provided, in addition leaf and stem anatomy are compared between the new and allied species and key of Lepidagathis Willd. in Tamil Nadu for easy identification is also provided.

KEYWORDS: Acanthaceae, Lepidagathis, Dharmapuri district, Eastern Ghats, endemic, South India, Morphoanatomy


 Lepidagathis decumbens N. Dhatchan. & S. Soosairaj, sp. nov.:
 A, flowering branch; B, inflorescence; C, bract; D, bracteole; E, flower; F, posterior sepal; G, lateral sepal; H, anterior sepals; I, corolla split open; J, stamen; K, pistil; L, capsule; M, seed.
Scale bars: A, B, 1 cm; C, D, F-H, 5 mm; E, I, K, L, 2 mm; J, 1 mm; M, 3 mm.
(drawing by P. Raja)

 A-D, Lepidagathis diffusa C.B.Clarke;
E-H, Lepidagathis decumbens N. Dhatchan. & S. Soosairaj, sp. nov.:
A, E, habit; B, F, inflorescence; C, G, flower; D, H, seed.

Lepidagathis decumbens N. Dhatchan. & S. Soosairaj, sp. nov.

Lepidagathis decumbens sp. nov. resembles L. diffusa C.B. Clarke,but differs in having erect and decumbent habit, short internodes,long unilateral spikes, multicelled glandular hairs, sericeous floralparts and ovate-suborbicular seeds.

Etymology. — The species epithet “decumbens” describes the erect and geniculate habit of the plant.

Distribution. — Lepidagathis decumbens sp. nov. is endemic to Dharmapuri district of Tamil Nadu, South India. 



 Narayanasamy Dhatchanamoorthy, Chinnasamy Karthikeyan, Prakasam Raja, Sebastian Soosairaj and Natesan Balachandran. 2022. Lepidagathis decumbens N. Dhatchan. & S. Soosairaj, sp. nov. (Acanthaceae), A New Species from Tamil Nadu, India.  ADANSONIA 44 (24); 321-329. adansonia.com/44/24