There is also a disjunct population in South America, with locations in central Chile and western Argentina.

Lupinus microcarpus is an annual plant growing to 80-centimetre (31 in) tall.

The flowers are generally pink to purple in color, but can also be between white and yellow; they are produced in open whorls on an erect spike.

Lupinus microcarpus grows from sea level in the north of its range, up to 1,600-metre (5,200 ft) high in Southern California.

There are three named botanical varieties: Chilean scientists (Universidad de Santiago de Chile) studying phytoremediation waste management in the city of Antofagasta, discovered that plants are capable of absorbing arsenic from the soil.