fabids

Fabids, also known as Fabidae or eurosids I in older classifications, are a major clade within the Rosids, one of the two primary lineages that make up the Rosids alongside Malvids. The group is defined principally by molecular phylogenetic data rather than a single universal morphological trait, and they group together a large portion of the world's flowering plants.

The Fabids include several orders such as Fabales (the legumes), Rosales (including roses and relatives), Fagales (oaks and beeches), and Cucurbitales (cucurbits). Together these orders encompass numerous families, species, and habitats, from temperate forests to tropical regions, and they contain many economically important plants.

A prominent feature of the clade is the inclusion of the legume family Fabaceae, which forms nitrogen-fixing symbioses with rhizobia in root nodules. Other Fabid lineages are valued for timber (Fagaceae), fruit crops (Rosaceae), and vegetables and gourds (Cucurbitaceae). The diversity of growth forms ranges from herbaceous plants to large trees.

In contemporary classifications such as APG IV, Fabids are placed within the Rosids as a monophyletic group, sister to the Malvids. The name reflects the legume family’s importance in defining the group, though it now denotes a broader lineage defined mainly by molecular relationships.