Flowers: small; clustered in a spherical head. Calyx: four-lobed. Corolla: tubular; four-lobed; within hairy. Stamens: four. Pistil: one, protruding, with a button-like stigma. Leaves: opposite, or whorled in threes; oval; on petioles; stipules between the leaves. A shrub five to ten feet high, with rough, grey bark.
The button-bush is like the children that cannot believe they are by the water until they have taken off their shoes and stockings and gone in paddling. It has usually its lowest stems and roots immersed in some brook or river; and we are invariably delighted with the curious, quaint effect of its bloom. The flower-heads are like little pin-cushions full of pins. Their perfect symmetry and the beauty of each flower when examined separately makes them a pleasing study.