Acmella radicans ( Jacq . ) R . K . Jansen ( Asteraceae )-a new angiosperm record for Bangladesh

A floristic survey was conducted throughout the Pablakhali Reserve Forests of Rangamati district of Bangladesh from May, 2014 to December, 2015. During this survey the representative specimens of almost all vascular plants available in this virgin forest were collected. After the critical taxonomic studies on the specimens of the family Asteraceae, few were finally identified as Acmella radicans (Jacq.) R.K. Jansen, which has been reported here as a new angiospermic record for Bangladesh.

The species Acmella radicans, commonly known as 'White spot-flower plant', is native to Central and South America and widespread in New and the Old world tropics or warm climate areas around the world (Sivarajan & Philip, 1984;Stevens et al., 1998;Raja et al., 2013).This species or its basionym Spilanthes radicans Jacq.has never been reported from the floristic area covering the present territory of Bangladesh by any literature before (viz.Hooker, 1879;Prain, 1903;Heinig, 1925;Raizada, 1941;Khan & Banu, 1969;Khan, 1992;Pasha & Uddin, 2013;Rahman et al., 2015 etc.;Ahmed et al., 2008;Rahman et al., 2008), though it has been reported from several areas of India (e.g., Sivarajan and Philip, 1984;Bhowmik et al. 2013;Raja et al., 2013;Jagtap & Bachulkar, 2015;Patel et al., 2015).In this study, Acmella radicans (Jacq.)R.K. Jansen has been reported for the first time from Bangladesh following a critical taxonomic investigation on the specimens of Asteraceae collected from the ethnic homestead area of Parachara hill of Pablakhali Reserve Forest belonging to Rangamati district and relevant literatures.The specimens are presently housed at Jahangirnagar University Herbarium (JUH), Savar, Dhaka, Bangladesh.The detailed description and illustration of the species based on herbarium material are given below.
Flowering and Fruiting: August-January.
Notes: The specimens of Acmella radicans (Jacq.)R.K. Jansen examined and its population found in the study area belongs to the variety A. radicans (Jacq.)R.K. Jansen var.radicans.This variety is distinct from another variety of the species A. radicans var.debilis (Kunth) R.K. Jansen by its discoid heads and achenes usually without evident corky margins at maturity in contrast to radiate heads and evident corky margins of achenes of A. radicans var.debilis (Jansen, 1985;Jagtap et al., 2015).
Acmella var.radicans seems similar to and often confused with Acmella paniculata from which it is distinctive by its axillary or terminal cluster of 2-3 heads, 4-merous white florets, and achenes lacking an evident corky margin at maturity and with or without a few tuberculae on the surfaces.In contrast, A. paniculata has solitary terminal or axillary heads, usually 5-merous, sometimes 4-5-merous yellow florets, and mature achenes with an evident cork-like margin and moderately to densely tuberculate surfaces.
Uses: Acmella radicans produces at least seven alkamides (Cortez-Espinosa et al., 2011).The uses of the Acmella radicans in traditional medicine can be generally summarized as follows: (a) relieve toothache and affections of throat and gums as well as to paralyse the tongue; (b) flower heads are known as a popular remedy for stammering children.A tincture made from the flower heads is also substituted for a tincture of pyrethrum for the treatment of inflammation in the jaw-bone; (c) seeds are regarded as a stimulant and sialagogue common cold, fever, and cough; (d) whole plant is boiled in water and the liquid as well as the solid are administered against dysentery; (e) a decoction is used as a diuretic and lithotriptist agent and employed as a bath against rheumatism, but also as a lotion against scabies and psoriasis; (f) juice of the plant is effective as a vulnerary and the pounded herb as a poultice to dress wounds and (g) roots are used in several parts of India as a purgative, while the whole plant is a fish poison (CSIR, 1982;Rios-Chavez et al., 2003).