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..
Euphorbia petaloidea Engelm. Bot. Mex. Bound.
Surv. 185. 1859. C. petaloidea Small, Fl. SE. U. S. 711. 1903.
Annual, pale green, glabrous. Stem usually rather stout, erect, branched above, 6'-2° high; leaves opposite, linear, oblong or linear-lanceolate, 5"-1' long, obtuse, usually flat, straight, entire, slender-petioled; stipules a fringe of setae; involucres solitary in the axils, oblong-campanu-late, 1" long, bearing 4 wineglass-shaped glands about as long as the lobes, each subtended by a white ovate or orbicular entire or undulate appendage; peduncles as long as the involucres; capsule globose-reniform, 1" long; seeds oblong-ovoid, nearly 1" long, ash-colored, minutely pitted, nearly terete.
Euphorbia petaloidea var. Nuttallii Engelm. Bot. Mex.
Annual, bright green, glabrous. Stem slender, erect or ascending, branched, 4'-2° high, the branches wiry, leaves mostly linear and mucronulate or truncate at the apex, often involute, obtuse or narrowed at the base, petioled, usually curved, the midvein prominent; stipules lanceolate or subulate-lanceolate; involucres solitary in the axils, campanulate, less than 1" long, long-peduncled, bearing 4 saucer-shaped glands subtended by white entire oblong or ovate appendages; seeds ovoid, 3/4" long, gray, 4-angled.
Prairies, Missouri and Kansas to Texas and Mexico. June-Sept.
Euphorbia Fendleri T. & G. Pac R. R. Rep. 2:
175. 1855. Chamaesyce Fendleri Small, Fl. SE. U. S. 710. 1903.
Annual (or perennial by a woody root), pale green, glabrous. Stem diffusely branched from the base, the spreading wiry branches 4'-8' long, brittle; leaves suborbicular, oval or elliptic, 1 1/2"-4" long, obtuse, entire, short-petioled, the base oblique, obtuse or subcor-date; stipules usually a fringe of short setae; involucres solitary in the axils, sometimes clustered toward the ends of the branches, campanulate, 1"-2 1/2" high, with 4 or 5 saucer-shaped oval glands subtended by irregular entire or slightly lobed appendages; peduncles about as long as the involucres; capsule deflexed, 1 /2" in diameter, sharply 3-lobed; seeds ovoid, 3/4" long, transversely wrinkled.
Nebraska and Wyoming to Texas, Mexico, Utah and Arizona. April-Oct.