Research Article |
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Corresponding author: Navendu V. Page ( navendu.page@gmail.com ) Academic editor: Hanno Schaefer
© 2025 Navendu V. Page, Tejas U. Thackeray.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Page NV, Thackeray TU (2025) Euonymus pushpagiriensis (Celastraceae), a new species from the central Western Ghats of Karnataka, India. PhytoKeys 253: 1-9. https://doi.org/10.3897/phytokeys.253.138418
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Euonymus pushpagiriensis sp. nov., an understorey tree species from the montane (Shola) forests of Kodagu District of Karnataka is described and illustrated. The species is morphologically distinct from all other species of Euonymus reported from the Western Ghats and the rest of India, in having sub-sessile, ovate leaves with rounded to sub-cordate leaf base. This species is, so far, known from the Kodagu District of the State of Karnataka.
Endemic, Euonymus, India, Kodagu, Western Ghats
The genus Euonymus is represented by roughly 145 species of woody plants. It is distributed in the tropical and temperate regions of the Northern Hemisphere, mainly across North America, Europe, South and South East Asia. Its distribution range, however, also extends into some of the tropical regions of Southern Hemisphere including Madagascar, Papua New Guinea and north-eastern Australia (
In India, the genus is represented by ca. 30 species (Ramamurthy 2000;
From year 2010 to 2014, plot-based inventory of woody flora of the evergreen forests of the Western Ghats, was carried out as part of the PhD study of the first author. Details about the sampling methodology and sampling locations are presented in
India. • Karnataka State, Kodagu District, Mandalpatti, alt. 1240 m, 12°32'23.02"N, 75°42'10.66"E, 28 April 2013 (fl.), N.V.Page 28413 (holotype: MH!; isotypes MH!, JCB!)
Euonymus pushpagiriensis can be distinguished from other species of Euonymus from the Western Ghats based on its sub-sessile leaves (petiole ca. 1 mm long) and ovate lamina with rounded to sub-cordate base. In contrast, all the other species of Euonymus from the Western Ghats of south India exhibit leaves with a distinct petiole (greater than or equal to 3 mm length) and elliptic, rarely ovate lamina with obtuse, acute or cuneate base.
E. pushpagiriensis (Figs
Euonymus pushpagiriensis A branches with light brown young and dark green mature leaves B abaxial surface of a leaf with sub-sessile nature, rounded leaf base, entire leaf margin, inconspicuous nerves and acuminate leaf apex with obtuse tips. Note the ducurrent nature of petiole which forms narrow wings extending along the inter-node. Photographs by Navendu Page.
Key characters that distinguish Euonymus pushpagiriensis sp. nov. from its morphologically closely-related species Euonymus angulatus.
| Character | E. angulatus | M. pushpagiriensis |
|---|---|---|
| Petiole | ≥ 3 mm long | ≤ 1 mm long |
| Leaf lamina shape | Elliptic | Ovate- lanceolate |
| Leaf base | Acute or obtuse, never rounded or sub-cordate | Rounded or sub-cordate |
| Leaf margin | Usually entire, rarely with a few serrations, not revolute | Always entire, obscurely revolute |
| Inflorescence | Borne from axils of older leaves from the last year’s growth | Borne only in the axils of terminal pair of leaves |
| Peduncle | Usually drooping, flexuose | Erect, rigid |
| Pedicel | Curved upwards | Erect, not curved |
| Capsule | Turbinate, deeply 5-lobed, attenuate at the base | Obovoid, with 5 angles and shallow grooves |
| Distribution | Mid to high (1000–1600 m) elevation forests on the windward slopes of Nilgiri and south Western Ghats of Kerala State | High (1200–1550 m) elevation forests of Pushpagiri mountain range in the Kodagu District of Karnataka State |
Understorey, evergreen shrubs or small trees, up to 3 m tall. Twigs glabrous, narrowly 4-winged, quadrangular in cross section, bud scales minute, usually persistent at nodes. Leaves opposite, lamina glabrous, thick, coriaceous, 3.5–5.5 × 1.5–2.7 cm, ovate; base rounded or subcordate; apex acute to acuminate, rounded at the tip; margin entire, obscurely revolute; petiole stout, ca. 1 mm, decurrent in to the wings of the stem; mid-vein distinctly raised adaxially, as well as abaxially; lateral nerves inconspicuous, 4–7 on each side of mid-vein, looping at the margin. Inflorescences compound dichasium, solitary, borne in the axils of the terminal leaves; primary peduncles four angled, 1.3–1.7 cm long; secondary peduncles up to 0.5 cm long; bracts at the base of primary and secondary peduncles, lanceolate,1–1.5 mm long. Flowers 6–15 per inflorescence, 5-merous, ca. 7 mm in diameter; sepals subequal, subround, 1–1.5 × 0.5–1 mm, margin erose; petals subround, 2–2.5 × 2.5–3 mm, red, margin white, finely crenulate; disc 5-lobed, ca. 2.5 mm in diameter; stamens 5, inserted in the middle part of the lobes of the disc, filaments subsessile; ovaries superior, 5-angled, stigmas round, short; ovules 2 per cell. Capsules obovoid, with 5 angles and shallowly grooved, apex concave, 1.4–1.6 × 1.1–1.3 cm, opening into 5-lobes at maturity. Seeds (1) 2 in each cell, ellipsoid, 5–6 × 4–5 mm, orange, partially covered by orange arils at base.
India. • Karnataka State: Kodagu District, Pushpagiri Peak, Pushpagiri Wildlife Sanctuary 12°39'42"N, 75°41'05"E, alt. 1550 m, 29 xii 2015, N.V.Page 291215 (JCB).
Euonymus pushpagiriensis is so far known from two localities and is endemic to the Kodagu District of Karnataka.
The species is distributed in the understorey or the edge of montane evergreen ‘Shola’ forests between 1200 to 1550 m elevation. The species was found to be growing in association with Nothopegia sp., Actephila excelsa, Memecylon sp. and Syzygium lanceolatum, amongst others. The species on both occasions was observed growing at the crest of the west-facing slopes of the Western Ghats.
Euonymus pushpagiriensis produces young leaves in the month of January. Flowering was observed from late April to May while the fruiting period starts from June and the fruits mature in the months of December and January.
The specific epithet refers to the type locality of species – Pushpagiri which is the name of the second highest peak in Kodagu District and the fourth highest peak in the State of Karnataka and also the name of the Wildlife Sanctuary in which the peak the located. The species is, so far, known only from Pushpagiri Wildlife Sanctuary and its adjacent areas.
The species is currently known from two locations within the Kodagu District of Karnataka State. The Area of Occupancy (AOO), as per the IUCN Red List guidelines, is estimated to be 8 km2. Based on the geographic range (Criteria B2), the species qualifies for the Critically Endangered category. However, the species does not meet two of the three conditions required for to qualify for the threatened category. It satisfies only the condition (a) which is that of the number of locations being less than five. There is no evidence to suggest a continuous decline (condition b) or extreme fluctuations (condition c) in range size or number of locations. Hence, Euonymus pushpagiriensis is provisionally assigned ‘Near Threatened’ category.
We would like to thank the Karnataka Forest Department for granting research permits. First author is grateful to Rohit Naniwadekar and Jahnavi Joshi for accompanying him during the follow-up field visits to confirm the novelty of the species. We are grateful to an anonymous reviewer and Hanno Schaefer, the handling editor for their valuable comments on the manuscript.
The authors have declared that no competing interests exist.
No ethical statement was reported.
Fieldwork was supported by Rufford Small Grant Foundation.
All authors have contributed equally.
Navendu V. Page https://orcid.org/0000-0002-9413-7571
Tejas U. Thackeray https://orcid.org/0000-0002-9981-8763
All of the data that support the findings of this study are available in the main text.