Polyandria

Polyandria is a historical classification used in Linnaean botany to group flowering plants whose androecium, or male floral parts, consists of a large number of stamens. The name derives from Greek poly- meaning many and andr- meaning male or stamens. In the Linnaean sexual system, plants were categorized by the number of stamens into a sequence of classes such as Monandria (one), Diandria (two), Triandria (three), up to Decandria (ten) and beyond. Polyandria referred to those genera whose stamens were numerous, typically well above ten, though there was no universally fixed numerical cutoff and authors varied in applying the class.

The class represented an artificial grouping rather than a natural lineage. It organized plants primarily by a single morphological feature—the abundance of stamens—without accompanying information about evolutionary relationships. As a result, similar stamen-rich plants from unrelated lineages could be placed in Polyandria, while completely different groups could appear in the same broader category.

Historical context and decline: Polyandria was used in the late 18th and early 19th centuries as part of the broader Linnaean effort to classify plants by visible reproductive traits. As botanical science progressed toward more natural, composition-based systems and later modern phylogenetic methods, the Linnaean classes based on stamen count were abandoned in favor of classifications rooted in evolutionary relationships.

Modern status: Polyandria is now considered obsolete in contemporary botanical nomenclature. Modern taxonomy relies on phylogenetic relationships and broad, natural groupings rather than the number of stamens to define plant families and higher taxa.