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..
Low annual mainly glabrous herbs, usually with opposite sessile or sometimes petioled leaves, 4-angled stems, and axillary mainly solitary small flowers. Calyx campanulate or globose, 4-lobed, the sinuses appendaged. Petals 4 in our species. Stamens 4, short. Ovary free from the calyx, globose, 4-celled. Capsule globose, enclosed by the membranous calyx, 4-celled, septicidally dehiscent, the valves very minutely and densely striate transversely.
[Latin, wheel, from the whorled leaves of some species.]
About 30 species, of wide geographic distribution in warm and tropical regions. Type species: Rotala verticillaris L.
Ammannia ramosior L. Sp. Pl. 120. 1753.
Ammannia humilis Michx. Fl. Bor. Am. 1: 99. 1803.
Boykinia humilis Raf. Aut. Bot. 9. 1840.
Glabrous, branched from the base or simple, ascending or erect, 2'-13' high. Leaves oblong or linear-oblong, 6"-15" long, 1"-3" wide, blunt at the apex, narrowed and sessile at the base or tapering into a short petiole, not auricled; flowers solitary or rarely 3 in the axils, very small; petals minute; style almost none.
4. DÉCODON J. F. Gmel. Syst. Veg. 2: 677. 1791. Herbaceous shrubs, with verticillate or opposite, short-petioled entire leaves, and showy purple pedicelled trimorphous flowers, in nearly sessile axillary cymes. Calyx broadly campanulate, or hemispheric, nerved, 5-7-toothed, with as many slender elongated accessory teeth in the sinuses. Stamens 10, rarely 8, alternately longer and shorter, inserted on the calyx-tube, the longer exserted. Style filiform; stigma small. Capsule globose, 3-5-celled, included in the calyx, loculicidally dehiscent. [Greek, ten-toothed, referring to the calyx.] A monotypic genus of eastern North America.
Lythrum verticillatum L. Sp. Pl. 446. 1753. Decodon aquaticus J. F. Gmel. Syst. 2: 677. 1791. Decodon verticillatus Ell. Bot. S. C. & Ga. 1: 544. 1821. Nesaea verticvillata H.B.K. Nov. Gen. 6: 191. 1823.
Aquatic, perennial, somewhat woody, with angular recurved glabrous or slightly pubescent stems 3°-10° long, which root from the tip when they reach the water or mud. Leaves lanceolate, 2'-5' long, 4"-12" wide, glabrous above, somewhat pubescent beneath, acute at both ends; petioles 2."-4' long; cymes several-flowered; flowers nearly 1'broad; petals cuneate at the base, pink-purple; filaments of the longer stamens very slender; capsule about 2 1/2" in diameter.
In swamps, Maine to Florida, west to southern Ontario, Minnesota, Tennessee and Louisiana. Stems clothed with parenchyma at the base. Flowers rarely double. Ascends to 2000 ft. in Pennsylvania. July-Sept. Peat- or slink-weed. Wild oleander. Grass-poly. Milk willow-herb.
Lagerstroemia indica L., crape myrtle, a large shrub with terminal panicles of showy white to purple irregular flowers, native of the East Indies is sparingly escaped from cultivation from Maryland southward.