This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", 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, with opposite petioled simple deciduous leaves, and no stipules. Flowers large, terminal or axillary, corymbose, racemose or solitary, white or cream-colored. Calyx-tube top-shaped, adnate to the ovary, 4-5-lobed. Petals 4-5, convolute, rounded or obovate. Stamens 20-40, inserted on the disk; filaments linear. Ovary 3-5-celled; styles 3-5, filiform, distinct, or united at the base; ovules . Capsule top-shaped, 3-5-celled, at length loculi-cidally dehiscent by 3-5 valves, many-seeded. Seeds oblong, the testa membranous, produced at each end. [Named after King Ptolemy Philadelphus.]
About 50 species, natives of North America, Mexico, Asia and central Europe. Besides the following, about 25 others occur in the southern and western parts of North America. Called Mock Orange from the orange-like blossoms of the various species. The common name Syringa is unfortunate, being the generic name of the Lilac.
Flowers inodorous, solitary or few.
Calyx-lobes about equalling the tube.
Calyx-lobes about twice as long as the tube.
Flowers racemose, numerous, fragrant.
Philadelphus inodorus L. Sp. Pl. 470. 1803.
A shrub, 6°-8° high, glabrous or very nearly so throughout. Leaves ovate or oval, acute or acuminate at the apex, rounded or sometimes narrowed at the base, 2'-5' long, strongly 3-nerved, serrate with small distant teeth, or entire; flowers white, inodorous, about 1' broad, solitary or 2 or 3 together at the ends of short branches; calyx-lobes triangular-ovate, acute, about as long as the tube; capsule about 3" high.
A shrub, 6°-10° high, resembling the preceding species and perhaps not specifically different. Leaves broadly ovate or oval, more or less pubescent, especially beneath, 3'-5' long, acuminate at the apex, rounded or narrowed at the base, sharply dentate, 3-nerved; flowers 1-3 together at the ends of the branches, and sometimes also axillary to the upper leaves, white, inodorous, 1 1/2'-2' broad; calyx-lobes lanceolate, acuminate, twice as long as the tube; capsule about 3" high.
In low grounds, Pennsylvania to Virginia, Tennessee and Florida. April-May.
Philadelplius coronarius L. Sp. Pl. 470. 1753.
A shrub 8°-10° high. Leaves short-petioled, oval, elliptic or ovate-elliptic, 2-4' long, glabrous above, pubescent beneath, acute or acuminate at the apex, rounded or narrowed at the base, denticulate with distant teeth. 3-nerved; flowers numerous, racemose at the ends of the branches, 1'-1 1/2' broad, creamy white, very fragrant; calyx-lobes ovate, acute, longer than the tube.