Neptunia lutea (Leavenw.) Benth.

Taxonomic Identity

Neptunia lutea (Leavenw.) Benth. is a trailing, vine-like perennial plant.

Stem Characteristics

Its stems are covered with soft spines, but it is far less prickly than the similar-looking Mimosa nuttallii.

This plant has sprawling stems that branch frequently, and each branch can grow up to 5 feet long.

Leaf Structure

Its leaves are alternate, stalked, and bipinnate, bearing a strong resemblance to tiny fern fronds.

Inflorescence Arrangement

The flowers are tiny, arranged in a slightly elongated, congested inflorescence that holds 30 to 60 flowers per cluster.

Unopened bud clusters look very similar to green bramble fruits.

Individual Flower Structure

Each individual flower has five minute petals and ten stamens.

When the flowers open, the inflorescence appears as a puffy yellow ball, and usually only the long yellow stamens are visible.

Inflorescence Placement

Each inflorescence grows singly at the end of a slender stalk.

Leaf Movement

Like some Mimosa species, the leaves of Neptunia lutea exhibit rapid plant movement: they close when touched, as well as at night and during cloudy weather.