Amaranthus tricolor is now correct name for what we earlier knew as Amaranthus gangeticus. A. cruentus is now correctly known as A. hybridus subsp. cruentus. The two species are distinguished as under:
Terminal inflorescence alone usually spiciform, the axillary inflorescences ± rounded clusters-or if axillary spikes present, these with globose clusters at junction with stem; bracteoles terminating in awns which are fine, flexuose and hair-like above; perianth segments 3........................................................................ Amaranthus tricolor
Terminal and at least some (generally most) of the upper axillary inflorescences spiciform, without dense globose clusters at the junction of peduncle and stem; bracteoles terminating in stout, rigid awns; perianth segments usually 5.............. A. hybridus
Subsp. cruentus has shorter bracteoles of female flower (longest mostly 1-1.5 times as long as the perianth; 1.5-2 times in subsp. hybridus), Stigma-bases and upper part of lid of fruit scarcely swollen (swollen in subsp hybridus) , fruit with no distinct “neck” (distinct neck in subsp. hybridus).
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Dr. Gurcharan Singh
Associate Professor
SGTB Khalsa College, University of Delhi, Delhi-110007
Res: 932 Anand Kunj, Vikas Puri, New Delhi-110018.
Phone: 011-25518297 Mob: 9810359089
http://people.du.ac.in/~singhg45/