Panicle- a compound raceme; an indeterminate inflorescence in which the flowers are borne on branches of the main axis or on further branches of these.
The example on the left is meadow-sweet (Spiraea latifolia), and the one on the right is Meyer lilac (Syringa meyeri).
Photos by K. R. Robertson of plants cultivated at the Arnold Arboretum and the University of Illinois.