Journal of Threatened Taxa | www.threatenedtaxa.org | 26 June 2018 | 10(7): 11992–11994
Notes on the taxonomy and distribution of the Bengal Morning Glory Ipomoea rubens Choisy (Convolvulaceae) in India
J. Swamy 1 & Pragada Venkata Ramana 2
1 Botanical Survey of India, Deccan Regional Centre, Plot no. 366/1, Attapur (V), Hyderguda(P.O), Inner Ring Road, Hyderabad, Telangana 500048, India
2 Government Junior College, Kaviti, Srikakulam District, Andhra Pradesh 532322, India
1 firstname.lastname@example.org (corresponding author), 2 email@example.com
IpomoeaL. is the largest genus in the family Convolvulaceae. Globally, the genus is represented by ca. 650 species, mainly distributed in tropical and warm temperate regions of the world (Mabberley 2008).
During a short visit to the coastal areas of SrikakulamDistrict in Andhra Pradesh, the authors collected an interesting Ipomoea species in flower and fruit, which was later identified as I. rubens Choisy. Scrutiny of literature revealed that the species was first collected in 1829 from Silhet (today in Bangladesh) and named as Convolvulus rubens byWallich in 1829. Subsequently, it was collected from the Gualparaarea of Assam (Kanjilal et al. 1939) and Caragola Ghat in northern West Bengal (Clarke 1883; Prain 1894, 1908). Later, it was widely reported from tropical America, tropical Africa, Vietnam, Indonesia, Philippines, Thailand and Madagascar (Staples 2010). Consultation of major Indian herbaria (ASSAM, AUV, BSHC, BSID, CAL, MH, HY, SKU) show that, the species has not been re-collected from India after the collections of Kurz (Caragola), Jenkins & Gibson (Assam), Hamilton (Pirgunj &Goalpara), Simons (Gauhati), and Keenan (Cachar). Hence the present collection from coastal Andhra Pradesh is noteworthy and shows that its distribution extends to peninsular India. A detailed description with photographs is provided to facilitate easy identification.
Ipomoea rubens Choisy, Mém. Soc. Phys. Genève 6(2): 463. 1833. Convolvulus rubens Wall., Numer. List [Wallich] n. 1421. 1829. Lettsomia rubens C.B. Clarke in Hook.f., Fl. Brit. India 4: 195. 1883. Pharbitis fragrans Bojer, Hortus Maurit. 227.1837. Ipomoea fragrans Bojer ex Choisy in DC., Prodr. 9: 341, 393. 1845. Type: India, Wallich 1421 (lectotype G 00227258, designated by Wood et al. 2015: isolectotypes G, K-W !).
Perennial twining herb, up to 10m high. Stems 0.7–1.2 cm in diam., hollow, terete, striate when dry, densely velutinous. Leaves simple, alternate, broadly ovate, 5.5–14 x 4–11 cm, deeply cordate with rounded auricles at base, margin entire, acuminate with mucronulatetip at apex, adaxially tomentellouswhen young, become glabrescent when mature, abaxially sericeous/grey-tomentose; lateral nerves 7–9 pairs; petiole slender, striate, 3–4 cm long, densely velutinous. Inflorescence axillary formed of 1-13-flowered cymes; cymes sub-umbellate; peduncles 2.5–13 cm long, secondary peduncles up to 9mm long, densely velutinous; pedicels 5–12 mm long. Flowers pink with dark at centre, ca. 4cm long. Bracteoles linear, ca.3 x 0.6 mm, deciduous before anthesis, pilose without, glabrous within. Sepals slightly unequal, connate at base; outer sepals elliptic-oblong, ca. 9 x 3 mm, acute at apex; inner sepals ovate-elliptic, broader than outer ones, 7-8 x 3-4 mm, acute or obtuse at apex; both sepals pilose above, sparsely pubescent on veins beneath. Corolla funnel-shaped, pink with dark centre, 4–5 cm long; tube 2cm long; limb 5–6 in diam., sparsely sericeous apically. Stamens 5, unequal, 9.5–18 mm long, included; filaments 7–14 mm long, dilating and hairy at base, glabrous above; anthers 4 x 1 mm long, subacuteat apex, cordate at base; tail ca. 9mm long. Ovary 1.2 x 1 mm long, 2-celled, glabrous; style slender, ca. 1.5cm long, glabrous; stigma bilobed; lobes globoseunequal. Capsule globose with persistent style, 1.5-1.8 mm in diam., enclosed by sepals, glabrous, 4-seeded. Seeds dull black, ca. 6 x 4.5 mm long, pilose (Image 1).
Flowering and Fruiting: December-March.
Distribution: Bangladesh, India (Andhra Pradesh, Assam and West Bengal), Thailand, Vietnam, Indonesia, Philippines, tropical America, and tropical Africa including Madagascar.
Habitat: Occasional in fresh water swamps near the coast; associated with Colocasia esculenta (L.) Schott, Glochidion zeylanicum (Gaertn.) A.Juss.,and Pandanus odorifer (Forssk.) Kuntze
Specimens examined: 2978 (BSID), 05.i.2017, India, Andhra Pradesh, Srikakulam, Kaviti, 19.014166670N 84.704722220E, 74m, coll. Pragada Venkata Ramana & J. Swamy (Image 2).
Additional specimen images seen: North Bengal, Caragola Ghat, 1 Oct.1868, S. Kurz s.n. (CAL0000027239); sin data, CAL0000027239, CAL0000027236.
Notes: The pilosesepals and grey-tomentose leaves of Ipomoea rubens can lead to confusion with I. longibarbis J.R.I. Wood & R.W. Scotland but the corolla is shorter and the bracts much smaller in the latter species. Moreover, I. rubens grows beside streams and lakes whereas I.longibarbis, grows in very dry scrub (Wood et al. 2015).
Clarke, C.B. (1883). Convolvulaceae. In: Hooker, J.D. (ed.). Flora of British India - Vol. 4. L. Reeve & Co., London, 195pp.
Kanjilal, U.N., A. Das, P.C. Kanjilal& R.N. De. (1939). Flora of Assam. Vol. III, Bishen Singh Mahendra Pal Singh, Dehra Dun, 344PP.
Mabberley, D.J. (2008). Mabberley’s Plant-book Aportable dictionary of plants - their classification and uses. 3rd edition. Cambridge University Press, Cambridge, U.K., 432pp.
Prain, D. (1894). Some Additional species of Convolvulaceae. Journal of the Asiatic Society of Bengal 2: 81–115.
Prain, D. (1908). Bengal Plants. Vol. II, BishenSingh Mahendra Pal Singh, Dehra Dun, p. 735.
Staples, G. (2010). Flora of Thailand, The Forest Herbarium, Department of National Parks, Wildlife and Plant Conservation, Bangkok, 330–468pp.
Wood, J.R.I., M.A. Carine, D. Harris, P. Wilkin, B. Wiliams& R.W. Scotland (2015). Ipomoea (Convolvulaceae) in Bolivia. Kew Bulletin 70: 3–124.