Asterales

File:A sunflower.jpg

A_sunflower

Asterales is an order of flowering plants that includes many well-known families such as the Asteraceae (daisy family) and the Campanulaceae (bellflower family). This order is part of the Asterids clade within the Eudicots, one of the two major groups of angiosperms (flowering plants).

Characteristics

Plants in the order Asterales typically have inflorescences that are arranged in a head (capitulum), which is a characteristic feature of the Asteraceae family. The flowers are often small and grouped together to form a composite flower head that can mimic a single flower. This arrangement is advantageous for attracting pollinators.

The leaves of Asterales are usually simple and can be arranged alternately, oppositely, or in a rosette. The flowers are generally bisexual and actinomorphic (radially symmetrical), although there are exceptions.

Families

The order Asterales includes the following families:

• Asteraceae - The largest family in the order, known for species such as sunflowers, daisies, and dandelions.
• Campanulaceae - Known for species such as bellflowers and lobelias.
• Goodeniaceae - Includes species like Scaevola.
• Menyanthaceae - Known for aquatic plants like Menyanthes.
• Calyceraceae - A small family of herbaceous plants.
• Stylidiaceae - Known for the trigger plants.
• Alseuosmiaceae - A small family of shrubs.
• Phellinaceae - A small family of shrubs and trees.
• Argophyllaceae - A small family of shrubs and trees.
• Pentaphragmataceae - A small family of herbaceous plants.

Evolution and Phylogeny

The Asterales are believed to have originated in the late Cretaceous period. Molecular phylogenetic studies have shown that the Asterales are closely related to the orders Apiales and Dipsacales within the Asterids clade.

Economic Importance

Many plants in the Asterales order are of significant economic importance. The Asteraceae family, in particular, includes many species that are cultivated for their ornamental value, such as chrysanthemums, marigolds, and zinnias. Additionally, some species are used for their medicinal properties, such as Echinacea.

Related Pages

• Asteraceae
• Campanulaceae
• Asterids
• Eudicots
• Angiosperms