Illustrative key for Amaranthus spp. in the Maltese Islands - by Stephen Mifsud.
Vers V3.82 (beta)

AMARANTHUS
L.
Amaranthus    Amarant
Family Description from Delta-key project by Watson & DalwitzList of species for this genus from the Plant List
Taxa left beyond this couplet: 13
A. blitoides
A. blitum
A. caudatus
A. cruentus
A. deflexus
A. gangeticus
A. graecizans subsp. sylvestris
A. hybridus s.l.
A. hypochondriacus
A. muricatus
A. retroflexus
A. tricolor
A. viridis
Description of Amaranthus
Annual, rarely perennial herbs; monoecious or dioecious. Leaves usually alternate. Bracteoles 3-5, small and herbaceous or membranous and spinescent. Perianth-segments 0-5, linear or lanceolate to spathulate. Styles and stigmas 2 or 3. Fruit dry, membranous, indehiscent or dehiscing transversely. Seeds vertically compressed.
Description by P. Aellen and J.R. Akeroyd extracted from Flora Europaea Vol 1-5 (Tutin et al., 1964-1993)
Amaranthus key steps >> 1
 
Lead

1.A

+
All flowers in clusters (or short spikes) in leaf axils, terminal spikes absent
ref

2

+ +
Inflorescences accompanied or overtopped by leaves
ref
OR
 
Lead

1.B

-
Flowers in terminal long spikes, sometimes present in leaf axils
 ref

4

- -
Inflorescences (spike) almost entirely leafless
ref
[A]     Illustration of Lead 1.A + [B]     Illustration of Lead 1.B - Identification Tips  
Plants with long terminal spikes and with some short ones at the leaf axils should be regarded with [B]
Image of A. blitoides (left) and A. graecizans (right) by Stephen Mifsud Image of A. hybridus (left); A. muricatus (top-right) and A. cruentus (bottom-right) by Stephen Mifsud -