The subfamily Spiraeoideae is a subfamily of flowering plants in the order Rosales.
Most are shrubs, but there are some herbs. Most have simple leaves, but the genera Aruncus and Sorbaria pinnately compound leaves. Carpels are distinct and few (2-5). Most members of the Spiraeoideae produce flowers that, upon seed-set, mature to form fruits that are aggregates of follicles.
Examples
Goats' Beard, Aruncus dioicus
False Spirea, Sorbaria sorbifolia
References
University of Illinois (http://www.life.uiuc.edu/plantbio/260/Rosaceae/Slide08.html) 2002-05-29
Traditionally it has been divided into 4 subfamilies (Rosoideae, Spiraeoideae, Maloideae or Pomoideae, and Amygdaloideae or Prunoideae), primarily diagnosed by the structure of the fruits, but this has not been universally followed.
Recent work has identified that the traditional four subfamilies are not all monophyletic, but the structure of the family is still awaiting complete resolution.
Subfamily Spiraeoideae: Traditionally those genera which bear non-fleshy fruits consisting of five capsules.