Asterids

The Asterids are a large and diverse clade (evolutionary grouping) of flowering plants (angiosperms) belonging to the Pentapetalae, itself a subclade of the eudicots. They represent one of the most species-rich groups within the flowering plants, comprising over a third of all angiosperm species.

The Asterids are characterized by several shared derived characteristics, although these features may not be universally present in all members due to evolutionary divergence and adaptation. Some common traits include sympetalous corollas (petals fused to form a tube or bell shape), a reduced number of stamens, and the presence of iridoid compounds (chemical compounds that may function as defense mechanisms). However, exceptions to these traits exist within the clade.

The Asterids are further divided into several major orders, including (but not limited to):

• Cornales: Includes dogwoods, hydrangeas, and allies.
• Ericales: Includes heaths, blueberries, tea, and related plants.
• Garryales: A small order including Garrya (silk-tassel bush).
• Gentianales: Includes gentians, coffee, and periwinkles.
• Lamiales: Includes mints, olives, snapdragons, and related species.
• Solanales: Includes potatoes, tomatoes, peppers, petunias, and morning glories.
• Apiales: Includes carrots, parsley, celery, and ivies.
• Aquifoliales: Includes hollies.
• Asterales: Includes sunflowers, daisies, asters, and lettuce.
• Dipsacales: Includes honeysuckles, valerians, and teasels.

The exact relationships and circumscription of orders within the Asterids have been subject to revision based on molecular phylogenetic studies. Ongoing research continues to refine our understanding of the evolutionary history and relationships of this important group of plants.