Bidens pilosa: A Sprawling Annual Weed

Origins and Characteristics

Bidens pilosa, commonly known as Spanish needles or black jack, is an annual herbaceous flowering plant native to South America. It has become naturalized worldwide and is now found in temperate and tropical regions. The plant is known for its small yellow and white flowers, as well as its barbed seeds that readily cling to clothing and fur.

Rapid Growth and Ground Coverage

One striking characteristic of Bidens pilosa is its rapid growth rate and ability to cover large areas of ground. Its stems can reach heights of up to 50 centimeters, and its sprawling habit allows it to spread widely. This makes it a potential nuisance in gardens and fields, as it can quickly crowd out other plants.

Global Distribution and Species Diversity

As a globally distributed species, Bidens pilosa is found throughout tropical and temperate regions. It is one of approximately 240 known species within the Bidens genus. Despite its widespread distribution, Bidens pilosa retains its distinct morphological and genetic characteristics, making it a recognizable species among the diversity of its genus.