This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Shrubs, or small trees, with opposite or verticillate short-petioled entire leaves, and terminal or axillary, densely capitate, bracteolate small white or yellow flowers. Calyx-tube obpyramidal, its limb with 4 obtuse lobes. Corolla tubular-funnel form, with 4 short erect or spreading lobes. Stamens 4, inserted on the throat of the corolla; filaments very short; anthers oblong, 2-cuspidate at the base. Ovary 2-celled; ovules solitary in each cavity, pendulous; style filiform, exserted; stigma capitate. Fruit dry, obpyramidal, 1-2-seeded. Endosperm cartilaginous; cotyledons linear-oblong. [Greek, head-flower.]
About 6 species, natives of America and Asia. The following, here taken as typical, is the only one known to occur in North America, unless the southwestern and Mexican plant proves to be distinct.
Cephalanthus occidentalis L. Sp. Pl. 95. 1753.
A shrub 3°-12° high, or sometimes a tree, up to 200 high, with opposite or verticillate leaves and branches, glabrous, or somewhat pubescent. Leaves petioled, ovate or oval, entire, acuminate or acute at the apex, rounded or narrowed at the base, 3'-6' long, 1'-2 1/2'wide; peduncles 1-3' long; heads globose, about I in diameter, the receptacle pubescent; flowers sessile, white, 4"-6" long; style very slender, about twice the length of the corolla; calyx-tube prolonged beyond the ovary.
In swamps, and low grounds, New Brunswick to western Ontario and Wisconsin, Florida, Texas, Arizona and California. Pond dogwood. Button-wood shrub. Box. Pin-ball. Little snowball. Button- or crane willow. Swamp-wood. River-or crouper-bush. June-Sept.