Heliantheinae

Heliantheinae is a subtribe of the tribe Heliantheae within the family Asteraceae. The group comprises predominantly herbaceous plants, many native to the Americas, and includes several well-known genera such as Helianthus (sunflowers) and Silphium (rosinweeds). The circumscription of Heliantheinae has varied with ongoing phylogenetic work, but it is generally recognized as containing genera that share certain morphological and genetic traits within Heliantheae.

Plants in Heliantheinae typically form composite flower heads (capitula) composed of ray florets, disk florets, or a combination of both. The inflorescences are often conspicuous and sun-oriented, with a color range from yellow to orange or reddish hues in many species. Leaves are usually alternately arranged and may be lobed or toothed. Fruits are cypselae, with pappi (if present) showing considerable variation across genera.

Ecology and distribution: Most members of Heliantheinae are adapted to open habitats such as prairies, meadows, disturbed grounds, and other sunlit environments. They serve as important nectar and pollen sources for a variety of insects and other pollinators. Several species are cultivated for ornamental purposes or for crop-related uses, with sunflowers being the most prominent example.

Taxonomy: The subtribal classification of Heliantheinae has undergone revisions as molecular phylogenetic studies have clarified relationships within Heliantheae. Consequently, some genera previously placed in Heliantheinae have been reassigned or redefined as data accumulated, reflecting a refined understanding of evolutionary relationships within the group.

Notable genera: Helianthus (sunflowers) and Silphium (rosinweeds) illustrate the diversity and economic relevance of the subtribe.