Eath Thora: Widespread Medicinal Herb in Asia and Noxious Weed in Northern Australia

Pic 1: Eath-thora plants– Sri Lanka

Pic 2: Eath- thora at flowering in Sri Lanka (January)

by Lalith Gunasekera

( February 29, 2016, Queensland, Sri Lanka Guardian) Eath- thora is a large handsome shrub originated in tropical Amazon Rainforest and can be found in Brazil, Colombia, Guyana, and Surinam. Due to its beauty, it has been cultivated around the world as an ornamental plant and has naturalised in many tropical regions in the world including tropical parts of Africa, India, Sri Lanka, Hawaii, the Caribbean, America, Fiji, Indonesia, Philippines, Thailand and Malaysia.

Botanical name: SENNA ALATA

Family: Fabaceae

Common names: Eath-thora (Sinhalese), semiagathi (Tamil), akapulka (Philippines) ringworm bush, craw-craw plant, seven golden stick, Christmas candle, king of forest, emperor’s candlestick (English).

Pic 1: Eath-thora plants– Sri Lanka

A widespread species with a scattered distribution throughout Northern and Eastern Australia. It is most common in the coastal and sub-coastal parts of the Northern Territory and northern Queensland and also recorded in north-western Western Australia.

Although eath-thora has a wide ecological amplitude, preferred habitats are disturbed, rather open vegetation’s such as roadsides, river banks, rain forest edges, lake shores, margins of ponds and ditches, in open forest edges and lake shores. The plant can be grown up to 1400 m altitude but is most abundant at lower elevations. It is reported to tolerate an annual rainfall of 600-4300 mm and average yearly temperatures of 15-30C. The plant is very susceptible to frost.

Eath-thora is an erect tropical bush that grows 2-3 m high with large leather compound leaves. Leaflets are 8-20 pairs; 5-17 cm long and 2-5 cm wide have entire margins and round tips. Compound leaves are alternatively arranged along the stems.

The golden yellow or orange flowers are borne in elongated clusters (15-60 cm) at the tips of the stems or in the upper leaf forks. These clusters are borne on hairy stalks 15-30 cm long and contain numerous (20-40) densely crowded flowers. The individual flowers are borne on short stalks. They are initially held within dark yellow or orange coloured bracts, but these fall off as the flowers open. Each flower has five petals and two stamens.

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