Star burr

Acanthospermum hispidum

Acanthospermum hispidum, commonly known as bristly starbur or goat's head, is an annual herbaceous plant belonging to the Asteraceae family. Native to the Americas, this plant has spread to various parts of the world and is known for its spiny fruits that can be troublesome in agricultural and natural settings. Here is an informative description of Acanthospermum hispidum, including its appearance, habitat, and ecological aspects:

Description:

  • Growth Form: Bristly starbur is an annual plant that grows upright, usually reaching heights of 30 to 60 centimeters (12 to 24 inches).

  • Leaves: The leaves are alternate, deeply lobed, and covered with bristly hairs, giving the plant its common name. The lobes often have sharp spines.

  • Stems: The stems are hairy and may become woody at the base as the plant matures.

  • Flowers: The small, yellow flowers are arranged in clusters at the ends of the stems. Each flower head consists of tubular florets surrounded by bristly phyllaries.

  • Fruits: The most distinctive feature of Acanthospermum hispidum is its fruit, a bur-like structure covered in bristles and spines. The bur contains one or more seeds that can attach to fur, clothing, or animal fur for dispersal.

Habitat:

Bristly starbur is commonly found in disturbed areas, including roadsides, fields, waste areas, and cultivated lands. It is adaptable to a range of soil types and environmental conditions.

Identification:

Identifying Acanthospermum hispidum involves recognizing its key features:

  1. Deeply Lobed Leaves: The leaves are deeply lobed and covered in bristly hairs.

  2. Spiny Margins: The leaf lobes often have sharp spines.

  3. Yellow Flowers: The small yellow flowers are arranged in clusters.

  4. Bristly Fruits: The most distinctive feature is the bur-like fruit covered in bristles and spines.

Ecological Impact:

  • Invasive Potential: Bristly starbur can be invasive and form dense stands, outcompeting native vegetation.

  • Seed Dispersal: The bur-like fruits are adapted for dispersal by attaching to animals or human clothing.

Management:

Managing bristly starbur is important to prevent its spread and impact on native ecosystems and agricultural settings. Control measures may include:

  1. Mechanical Control: Regular mowing or cutting can prevent the plant from producing seeds and reduce its spread.

  2. Herbicides: Selective herbicides may be used for targeted control, but care must be taken to avoid harm to desirable vegetation.

  3. Seed Removal: Promptly removing and disposing of plants before they produce seeds can help prevent further spread.

  4. Prevention: Implementing preventive measures, such as minimizing soil disturbance and monitoring for early infestations, can be effective.