Scientific Name: Macroptilium atropurpureum
Common Names: Purple Bushbean, Purple Bush-bean, Atro, Siratro
Growth Habit: Vine, Herb/Forb
Hawaii Native Status: Introduced. This fast growing, naturalized cattle forage plant is native to tropical and subtropical areas from the southern U.S. to South America.
Flower Color: Reddish black with a purplish tinge in the sunlight
Height: Trailing or twining to 4 feet (1.2 m) long
Description: The oddly colored, pea-shaped flowers are followed by long, slender bean pods that dehisce (split open) violently when mature, ejecting the seeds away from the parent plant. The leaves are dark green above, fuzzy below, and trifolate with three oval to rhomboid leaflets. The two side leaflets are often lobed, but only on one side (the outer side). The stems are twining and covered in fuzzy hair.
Here in Hawaii, Purple Bushbean is a weed in disturbed areas. It is commonly observed growing along roadsides and in overgrown pastures.
Wild Bushbean (Macroptilium lathyroides) is similar in appearance, but it has red flowers and narrower leaflets.
Kingdom: Plantae – Plants
Subkingdom: Tracheobionta – Vascular plants
Superdivision: Spermatophyta – Seed plants
Division: Magnoliophyta – Flowering plants
Class: Magnoliopsida – Dicotyledons
Family: Fabaceae – Pea family
Genus: Macroptilium (Benth.) Urb. – bushbean
Species: Macroptilium atropurpureum (Moc. & Sess ex DC.) Urb. – purple bushbean
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