Which grass subfamilies contain many C4 plants?

Within the grass family (Poaceae), the subfamilies that contain many C4 plants are the Chloridoideae and the Panicoideae.1

These two subfamilies are primarily concentrated in tropical regions and have evolved special adaptations for photosynthesis that allow them to tolerate relatively warm and dry habitats. The C4 pathway, which these plants utilize, involves a spatial separation of carbon fixation between mesophyll and bundle-sheath cells, helping the plants minimize photorespiration and conserve water in hot, dry environments. While other grass subfamilies exist, these two are specifically noted for their reliance on these photosynthetic adaptations.123