Composite aster Inula L. (Asteraceae): a new generic record for Nicobar Islands, India

The Andaman & Nicobar Islands popularly known as the ‘Emerald Isles’ are a Union Territory of India and the largest archipelago system in the Bay of Bengal, consisting of 306 islands and 206 rocks and rocky outcrops (islets). It is situated between 6045’–13041’N & 92012’–93057’E, covering 8,249km2 geographical area with a coastline of 1,962km. The topography of these islands, geologically, is a part of the land mass belonging to Southeast Asia, including Malaysia, northeastern India, Burma, Thailand and Indonesia. These islands stretch north–south in direction and simulating an arc stretching over a length of about 912km and with a maximum width of 57km. The terrain of the Andaman Islands (part of the Indo-Burma Biodiversity Hotspot) has been formed due to volcanic activity in contrast to the Nicobar Islands (part of Sundaland Biodiversity Hotspot), which were formed from the fragments of a continental land mass (Khan et al. 2012). These Islands harbour luxuriant low-land rain forests besides wetlands, mangroves and coral reefs. The floral elements of these Islands often show close affinity with that of Indonesia, Malaysia, Myanmar, Thailand and Sri Lanka. The phytodiversity of these islands is unique and one of the richest in the country in terms of biodiversity with a remarkable degree of genetic variations.

While working on ‘Quantitative Assessment and Mapping of Plant Resources of the Andaman & Nicobar Islands’, a project sponsored by the Department of Biotechnology, Ministry of Science & Technology, New Delhi, India, during 2010–2015, some specimens collected revealed that they were hitherto unreported from this archipelago. On critical study, consultation of literature (Rao 1986; Sinha 1999; Pandey & Diwakar 2008) and detailed examination, the specimens were identified belonging to Inula cappa, an aster. Since no records of Inula are reported from the Andaman & Nicobar Islands till date, this collection forms a new distribution record for the islands. Globally, Asteraceae contains ca. 1,900 plant genera and the genus Inula is represented by ca. 110 species (Plant List 2013). Descriptions along with illustrations are provided for this species to facilitate identification and future studies. The specimens collected were deposited in the herbarium of Botanical Survey of India, Andaman & Nicobar Regional Centre, Port Blair (PBL).

Inula cappa

(Buch.-Ham. ex D. Don) DC. Prodr. 5: 469.1836; Hooker, Fl. Brit. Ind. 3. 295. 1881; Brandis, Ind. Tree. 400. 1906. Conyza cappa Buch.-Ham. ex D. Don, Prodr. Fl. Nepal. 176. 1825. Duhaldea cappa (Buch.-Ham. ex D. Don) Pruski & Anderb. Compositae Newslett. 40: 44. 2003.

Specimens examined: 1742 (PBL-Acc.No.-32969), 07.v.2014, India, Andaman & Nicobar Islands, Great Nicobar Forest Division, Chowra Island, Thylla Village 8027’49.15”N & 9302’45.74”E, 15m, coll. S. Aron & R. Sathiyaseelan.

Description: Shrubs, up to 3m tall. Stems tomentose, branched. Petiole ca. 5–15 mm; leaf blade elliptic, lanceolate, or narrowly oblong, 10–25 × 2.5–5.5 cm, thick, rather papery, whitish lanate abaxially, obscuring minor veins, green and sparsely coarsely pubescent adaxially, base rounded (rarely tapered), margin remotely serrulate, apex acute or shortly acuminate. Capitula radiate or disciform, in dense corymbs. Involucre 6-seriate; phyllaries lanceolate, tomentose, inner ones 4.5–6 × ca. 0.7 mm. Ray florets few; corollas yellow, usually 4.5–5.5 mm, tubular and erect or curved outward or with short lamina to 1 × 1 mm, rarely tube 2.9–3.5 mm with lamina 2.3–2.9 mm. Disk floret, corolla yellow, 4.76 × 46 mm, lobes ca. 0.5mm, apically glandular; anthers weakly exserted, tailed, endothecial tissue polarized, apical appendage truncate; style branches ca. 1mm. Achene cylindric, ca. 1.8 mm, white tomentose. Pappus 4mm, dull-white, sometimes brown, hairs thickened at the ends.

Phenology: Flowers April–September; fruits July–November.

Habitat: Found growing in forest clearing of coconut plantation.

Distribution: Bhutan, China, India (northeastern India, Bihar, Himachal Pradesh, Jammu & Kashmir, Rajasthan, Uttar Pradesh, Uttarakhand, and now from the Andaman & Nicobar Islands), Laos, Malaysia, Myanmar, Nepal, Pakistan, Thailand and Vietnam.

References

Khan, P.K., A. Mohan & S. Chowdhury (2012). Pre- and post-seismic activities along the Myanmar-Andaman-Sumatra Subduction Margin: insights for tectonic segmentation. Journal of Indian Geophysical Union 16(3): 87–96.

Pandey, R.P. & P.G. Diwakar (2008). An Integrated Checklist of Andaman and Nicobar Islands, India. Journal of Economic and Taxonomic Botany 32(2): 403–500.

Rao, M.K.V. (1986). A preliminary report on the angiosperms of Andaman and Nicobar Islands. Journal of Economic and Taxonomic Botany 8:107–184.

Sinha, B.K. (1999). Asteraceae, pp. 277–285. In: Hajra, P.K. & P.S.N. Rao (eds.). Flora of Great Nicobar Island. Botanical Survey of India, Calcutta.

The Plant List (2013). Version 1.1. http://www.theplantlist.org [accessed 28-Oct-2015].