A morphological investigation was carried out in three Indigofera species (I. tinctoria, I. suffruticosa and I. amblyantha) with a view to identifying a set of characteristics for the individual indigo species. Distinct variation exists in stem colour; length of rachis of leaf; size, shape, colour and chlorophyll content of leaflet; number of leaflets/leaf; colour and size of flower; size, shape, colour of pod and seed. The species I. tinctoria possesses 5-11 obovate leaflets/leaf, pink flower, narrow cylindrical pod (average pod length, 28.9 mm) with slightly curved tip and cylindrical deep brown large seed (average 1000-seed weight, 5.79 g); I. suffruticosa possesses green stem with patches of reddish colour, 9-17 narrowly oblong leaflets/leaf, crimson flower, short strongly curved pod (average pod length, 14.5 mm) and cylindrical dark green small seed (average 1000-seed weight, 3.75 g); and I. amblyantha possesses 13-15 ovate to lanceolate large leaflets/leaf, cerise-violet flower with coloured tip of keel, long, thick, straight cylindrical pod (average pod length, 32.8 mm) and globose greenish yellow medium seed (average 1000-seed weight, 4.72 g).

A. B. M. Mahbub Morshed Khan, Lecturer, Department of Agricultural Botany,Patuakhali Science and Technology University (www.pstu.ac.bd),was born in 1981. He was awarded the university gold medal in MS degree in Crop Botany from Bangladesh Agricultural University. His research interest is in the field of plant physiology and ecology.