Citation: L., Sp.Pl. 989 (1753).

Synonymy: Not Applicable

Common name: Amaranths.

Description:
Annual herbs with alternate petiolate leaves, the lateral nerves conspicuous on the undersurface.

Flowers usually monoecious, small, with a bract and 2 bracteoles at the base, arranged in axillary or terminal clusters, greenish or less often reddish; perianth of 2-5 green or scarious segments; stamens 3-5, free; styles 2 or 3, stigmatic from the base.

Fruit membranous, with a separable pericarp, circumsciss or indehiscent or dehiscing irregularly, enclosed in the perianth; seed solitary, vertical, biconvex, black and shining.

Distribution:  About 60 species, almost cosmopolitan. Several species are grown for food or as ornamentals or are troublesome weeds. Many of the identifications on which this treatment is based are uncertain and a thorough revision is much needed.

Biology: No text

Key to Species:

1. Fruit circumsciss
2. Perianth-segments 2 or 3; flowers in axillary clusters
3. Bracteoles twice as long as the perianth, spinescent	A. albus 1.
3. Bractcoles not longer than the perianth, not spinescent	A. graecizans 5.
2. Perianth-segments 4 or 5; flowers in elongate spikes
4. Inflorescence distinctly reddish
5. Inflorescence drooping, many-branched; perianth 1.5-2 mm long	A. caudatus 2.
5. Inflorescence erect, few-branched; perianth usually 4-5 mm long	A. paniculatus 12.
4. Inflorescence mainly green
6. Perianth-segments linear or oblong, obtuse or emarginate	A. retroflexus 14.
6. Perianth-segments lanceolate or ovate to elliptic, acute
7. Longest bracts twice as long as the perianth .A. hybridus 7
7. Longest bracts up to about one and a half times as long as the perianth
8. Inflorescence branches few, if any; style branches recurved	A. powellii 13.
8. Inflorescence branches many; style branches erect	A. cruentus 3.
1. Fruit indehiscent or dehiscing irregularly
9. Flowers in globular clusters	A. macrocarpus 9.
9. Flowers in spikes
10. Spikes slender, 2.5-5 cm long; fruit globular, c. 1.5 mm long, corrugated	A. viridis 15.
10. Spikes thick, to 2.5 cm long; fruit ellipsoid, 2-3 mm long, smooth or wrinkled	A. deflexus 4.
11. Perianth-segments broad-spathulate, finally spreading distally, 2-6 mm long
12. Fruiting perianth 2-2.5 mm long	A. mitchellii 10.
12. Fruiting perianth 4-6 mm long	A. grandiflorus 6.
11. Perianth-segments narrow-spathulate or oblong, usually erect or incurved distally, to 2 mm long
13. Perianth-segments narrow-spathulate; leaves ovate or elliptic; plant erect or decumbent	A. interruptus 8.
13. Perianth-segments oblong; leaves linear-lanceolate; plant prostrate	A. muricatus 11.

Author: Not yet available