Description: Annual or perennial herbs or subshrubs.
Leaves alternate, imparipinnate, ± sessile; leaflets usually 5, upper 3 towards summit of rachis with lower 2 often smaller, stipule-like and ± stem-clasping; stipules minute or absent.
Inflorescences axillary, flowers ± sessile in umbels subtended by a 3-foliolate leafy bract; peduncle ± longer than subtending leaves, elongating in fruit. Calyx with 5 ± equal teeth or the lowest teeth longest, teeth ± longer than tube. Standard ovate to circular; wings obovate; keel incurved, apex acute and beaked. Stamens diadelphous, filaments alternatively long and short; anthers uniform. Ovary sessile, ovules numerous.
Pod linear, terete or compressed, transversely septate, contorting on dehiscence; seeds 1–many, globose, often compressed, without obvious aril.
Distribution and occurrence: World: >100 species, Mediterranean, temperate Eurasia, southern Africa, eastern North America, New Zealand. Australia: 7 species (2 species endemic), all States.
A number of species have been introduced as fodder crops and have become naturalized in surrounding districts.
Text by E. H. Norris & G. J. Harden
Taxon concept:
| | Key to the species | |
| 1 | Umbels usually 8–14-flowered. | Lotus uliginosus |
| Umbels mostly 1–7-flowered or occasionally to 8. | 2 |
| 2 | Flowers purple, red to pink or white. | 3 |
| Flowers yellow.
Back to 1 | 5 |
| 3 | Umbels 3–8-flowered, peduncles much longer than subtending leaves; corolla usually pink to white. | Lotus australis |
| Umbels 1–3-flowered, peduncles about same length or shorter than the subtending leaves; corolla usually red.
Back to 2 | 4 |
| 4 | Corolla <10 mm long; leaflets usually <10 mm long; pods not winged. | Lotus cruentus |
| Corolla >15 mm long; leaflets >10 mm long; pods with wings c. 2 mm wide.
Back to 3 | Lotus tetragonolobus |
| 5 | Flowers >9 mm long; umbels 2–8-flowered. | 6 |
| Flowers <9 mm long; umbels 1–4-flowered.
Back to 2 | 7 |
| 6 | Teeth of calyx equal to or shorter than tube; pods usually 1.5–3 cm long; perennials. | Lotus corniculatus |
| Teeth of calyx about 1.5 times as long as tube; pods mostly 3–4.5 cm long; annuals.
Back to 5 | Lotus preslii |
| 7 | Pods 6–15 mm long; umbels 2–4-flowered; keel with a long beak bent upwards from near base. | Lotus subbiflorus |
| Pods 20–30 mm long; umbels 1- or 2-flowered; keel with a short beak bent upwards from the middle.
Back to 5 | Lotus angustissimus |
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