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..
Annual, erect woolly or silky, branching or simple herbs, with opposite sessile entire or slightly undulate narrow leaves, or the lower and basal ones contracted into petioles. Flowers perfect, 3-bracted, often bracteolate, in panicled dense spikes. Calyx tubular, nearly terete, 5-cleft or 5-toothed, very woolly, its tube longitudinally crested and sometimes tuber-cled in fruit. Stamens 5, their filaments united into a tube, which is 5-cleft at the summit and bears the I-celled anthers between its lobes. Ovary ovoid; style slender or wanting; stigma capitate or penicillate. Utricle indehiscent, enclosed by the tube of united filaments. [Name in honor of J. A. Froelich, a German botanist.]
About 12 species, all American. Besides the following, 2 others occur in the Southwestern States. Type species: Gomphrena interrupta L.
Stout, 2°-4° tall; crests of fruiting calyx continuous, dentate.
Slender, 10'-20' tall; crests of fruiting calyx interrupted.
Froelichia campestris Small, Fl. SE. U. S. 397. 1903.
Stem stout, woolly, 2°-4° tall, the branches slender, erect-ascending, leafless above. Upper leaves linear or linear-oblong, sessile, acute or acuminate at both ends, 1'-3' long, the lower spatulate or oblanceolate, obtuse or acute at the apex, 3'-6' long, 1/2'-1' wide, narrowed into margined petioles; spikes mostly opposite, narrowly ovoid or oblong, obtuse or subacute, 1/2"-1' long; fruiting calyx with prominent longitudinal wing-like toothed crests.
In dry soil, Illinois and Minnesota to Nebraska and Colorado, Tennessee, Kansas and Texas. June-Sept.
Froelichia fioridana (Nutt.) Moq. in which this was included in our first edition, has a hairy, not woolly stem and calyx-crests more deeply cut. It inhabits the Southern States and is recorded from Delaware.
Froelichia gracilis Moq. in DC. Prodr. I32 420. 1849.
Similar to the preceding species but the stem slender, branched, especially from the base, or sometimes simple, 10'-20' tall. Leaves all linear or linear-oblong, acute at both ends, 9"-2' long, sessile or the lower commonly spatulate, obtusish and narrowed into very short petioles; spikes alternate or opposite, oblong, mostly obtuse, 1/4'-l' long; fruiting calyx with 5 longitudinal rows of processes or these confluent into interrupted crests.
In dry soil, western Missouri and Nebraska to Colorado and Texas. June-Sept.
Gomphrena globosa L., the Globe Amaranth, cultivated for ornament, native of the Old World tropics, with densely capitate red or white flowers, the filaments united into a long tube, has been found in waste grounds in Ohio.