Gen info
The genus Crotalaria comprises about 600 species distributed throughout the tropics and subtropical regions of the world.

Botany
Suso-susoyan is an annual herbaceous weed, differing from related species in having palmately compound leaves of five leaflets. Pods are bigger, about 7 centimeters long and 2 centimeters in diameter. When mature, the loose seeds rattle inside. Seeds are explosively dispersed from the pods.

Distribution
- Found in damp places, in waste lands and paddies.
- Used as ground cover and green manure.
- Native to the Philippines.
- Also found in India, Bangladesh, Sri Lanka, Cambodia, Vietnam, Indonesia, Malaysia.

Constituents
- Seeds yield a pyrrolizidinne alkaloid, monocrotaline.

Properties
- The pyrrolizidinne alkaloid, monocrotaline, is reportedly toxic to poultry.

Parts used
Leaves

Uses
Edibility
- Flowers are steamed and eaten as vegetable.
Folkloric
- Leaves mixed with those of Crotalaria retusa, consumed or applied externally for fever, scabies, lung afflictions, and impetigo. (6)
- Seedpods used for treating snake and millipede bites.
Others
- Fiber: Bark is a source of fiber.

Caution
• Toxicity to concern: Because of presence and toxicity of pyrrolizidines, there is potential concern of toxicity to humans and livestock.

Studies
• See studies on related species, C. retusa.
• Toxicity of Pyrrolizidine Alkaloids / Seeds: Seeds of 41 accessions of Crotalaria representing 35 species were analyzed for concentration of total pyrrolizidine alkaloids (PAs) and for oral toxicity to 1-week old chicks. All accessions were analyzed for the presence of monocrotaline and spectabiline by TLC and HPLC. High concentrations of PA were found in seed of C. spectabilis (3.85%), C. retusa (2.69%), C. alata (1.69%), C. quinquefolia (1.19%) and C. argyrolobioides (1.01%). No species contained both monocrotaline and spectabiline. (4)
• Toxicity to Domesticated Species: Among pyrrolizidine-containing plants, Crotalaria species caused the greatest range of tissue damage to domesticated animals i.e., cattle, sheep, goats, horses, and pigs, and liver damage in livestock. (Poisonous plants of Australia / Selwyn L. Everist) (5)

Availability
Wild-crafted.

Additional Sources and Suggested Readings
(1)
Crotalaria quinquefolia / Synonyms / The Plant List
(2)
Crotalaria quinquefolia / Useful Tropical Plants
(3)
Sorting Crotalaria names / Common names / Porcher Michel H. et al. 1995 - 2020, Sorting Crotalaria Names. Multilingual Multiscript Plant Name Database - A Work in Progress. Published by The University of Melbourne. Australia.
(4)
Occurrence, Concentration, and Toxicity of Pyrrolizidine Alkaloids in Crotalaria Seeds / Williams, MC; Molyneux, RJ / Weed Science, 1987; 35 (4): pp 476–481
(5)
Crotalaria / Wikipedia
(6)
Crotalaria retusa / Pl@ntUse