Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 April 2025 | 17(4): 26936–26938
ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print)
https://doi.org/10.11609/jott.9556.17.4.26936-26938
#9556 | Received 15 December 2024 | Final received 18 February 2025 |
Finally accepted 03 April 2025
Isodon neorensis Ranjan, G. Krishna
& Anant Kumar (Lamiaceae): a new record for
Sikkim Himalaya, India
Pramod
Rai
Ashoka Trust for Research in Ecology and the Environment,
Regional Office, Eastern Himalaya Northeast India, NH 10, Tadong,
Gangtok District, Sikkim 737102, India.
Editor: Afroz Alam, Banasthali Vidyapith,
Rajasthan, India. Date of publication: 26 April 2025
(online & print)
Citation: Rai,
P. (2025).
Isodon neorensis
Ranjan, G. Krishna & Anant Kumar (Lamiaceae): a
new record for Sikkim Himalaya, India. Journal of Threatened Taxa 17(4): 26936–26938. https://doi.org/10.11609/jott.9556.17.4.26936-26938
Copyright: © Rai 2025. Creative
Commons Attribution 4.0 International License. JoTT
allows unrestricted use, reproduction, and distribution of this article in any
medium by providing adequate credit to the author(s) and the source of
publication.
Funding: None.
Competing interests: The author declares no competing interests.
Acknowledgements: The author is grateful to Dr. Anant Kumar, Department of Botany and Microbiology, Hemvati Nandan Bahuguna Garhwal University, Uttarakhand, India, for his invaluable input during the preparation of the manuscript. The author would also like to thank the Department of Forest and Environment, Deorali, Gangtok, for granting permission to conduct field explorations.
The genus Isodon
(Schrad. ex Benth.) Spach (Lamiaceae: Nepetoideae: Ocimeae: Isodoninae) in India is represented by about 22 taxa
distributed mostly in eastern and peninsular India (Anonymous 2020; Ranjan et
al. 2022). During an exploration of Gangtok flora, an
interesting species of the genus Isodon was
collected from Daragaon region of Tadong,
Gangtok, Sikkim. The striking characteristics of the
species like red colored flowers on lax inflorescence were readily attractive.
On further morphological examination, consultation of relevant literature
(Ranjan et al. 2022; Wangchuk 2024) and herbarium consultation (CAL) revealed
its identity as Isodon neorensis
Ranjan, G. Krishna & Anant Kumar (2022). Isodon
neorensis was recently described from Neora Valley National Park, Darjeeling, West Bengal based
on the morphological characters. The
species was not yet recorded from the state (Anant Kumar 2024 pers. comm.). The
detailed description with notes on some variations, color plate is provided
here for easy identification.
Taxonomic description
Isodon neorensis Ranjan, G. Krishna & Anant Kumar., Taiwania 67(2): 261. 2022: Wangchuck,
S., Pleione 17(2): 218 – 221. 2023. (Image 1).
An erect herb, up to 1 m tall. Stems brown,
quadrangular, unbranched, scabrous, internodes 3–8 cm long. Leaves opposite;
petiole dark purplish, subterete, 3–6 cm long,
scabrous; lamina ovate to cordate, 2–8 cm × 2–5 cm, base cuneate, truncate or
cordate, margins bluntly dentate, apex acuminate, sparsely hairy above with
scabrous veins, minute brownish-dotted beneath; veins impressed above, raised
below. Inflorescence terminal or rarely axillary raceme composed of lax cymes,
10–25 cm, axis scabrid, cymes with peduncle 1–3 cm
long, proximally scabrid, distally glabrescent;
bracts broadly elliptic, ca. 1.5 cm across, scabrid;
bracteoles linear, ca.1 mm long, scabrid; pedicels
0.8–2 cm long, scabrid. Calyx campanulate, ca. 1 mm
long and sparsely glandular, anterior lip 2-lobed, ovate-oblong; posterior lip
3-lobed, each lobe triangular, apex acute; tube 8–10-nerved. Corolla maroon or
deep red with white blotch on throat, mixed with red dots, ca. 3.5 mm long,
glabrous; tube campanulate, ca. 2 mm long; posterior lip reflexed, 4-lobed,
apically rounded, throat hairy; anterior lip ovate or obovate, 1.5–1.7 mm long,
slightly concave, scattered glands outside. Stamens 4, dark red, exerted,
inserted at the middle of the corolla tube; filaments slender, ca. 3 mm long;
anthers flattened, elliptic, ca. 0.5 mm across, yellowish-white and black at
maturity. Style red, slender, gynobasic, ca. 5 mm long.
Flowering and fruiting: October–November.
Habitat: Growing on sub-tropical forest floor.
Dominant associated trees were Schima wallichii, Engelhardtia
spicata, Mallotus
denticulata, Pinus roxburghii,
Alnus nepalensis and
Leucosceptrum canum. The
population was growing in a disturbed habitat, on a highway roadside.
Associated understorey species were Hypoestes phyllostachya,
Asystasia macrocarpa, Dicliptera chinensis, Pilea scripta, and Ophiopogon intermedius. A single population
was found in the study area with 16 individuals distributed randomly.
Distribution: India (West Bengal, Sikkim), Bhutan (Ranjan
et al. 2022; Wangchuk 2024).
Specimen examined: India, Sikkim, Gangtok,
Daragaon, 27.3060 0N, 88.5926 0E,
1,190 m, 29 October 2024, Pramod Rai P0507 (BSHC).
Notes: I. neorensis
shares closeness with I. lopanthoides in the
region. However, they can be distinguished as follows;
Stem scabrous, inflorescence racemic, flowers
maroon or deep red, nutlet yellowish
………………….............................................……..
I. neorensis
1.
Stem glabrous to pubescent, inflorescence paniculate, flowers white,
nutlet brown ..............................................................................I.
lopanthoides
We also noted a few variations exhibited by our specimens
(leaf bases are mostly cordate, the feature not known hitherto, and thus
cordate leaves, a new shape variation of the species; flowering till October is
also the most extended period noted so far).
For image - - click here for full PDF
References
Anonymous (2020). Flowering Plants of India-An Annotated
Checklist (Dicotyledons). Botanical Survey of India, India. 2: 246.
Ranjan, V., G. Krishna
& A. Kumar (2022). A new species of Isodon (Lamiaceae) from Indian Eastern Himalaya. Taiwania 67(2): 260–266. https://doi.org/10.6165/tai.2022.67.260
Wangchuk, S. (2023). Isodon neorensis Ranjan, G. Krishna & Anant Kumar (Lamiaceae): a new record for Bhutan. Pleione 17(2):
218–221. https://doi.org/10.26679/Pleione.17.2.2023.218-221