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..
Gentiana pulchella Sw. Act. Holm. 1783: 84. f. 8, 9. 1783.
Gentiana ramosissima Vill. Hist. Pl. Dauph. 2: 530. 1787.
Erythraea ramosissima Pers. Syn. 1: 283. 1805.
Erythraea pulchella Fries, Novit. 74. 1828.
C. pulchellum Druce, Fl. Oxf. 342. 1897.
Annual, glabrous, much branched, 3'-8' high. Leaves oval, ovate or lanceolate, the lower mostly obtuse, 3"- 8" long, the upper usually acutish or acute and smaller; no basal tuft of leaves; flowers pink, cymose-paniculate, all or nearly all of them short-pedicelled, 5"-6" long; tube of the corolla 1 1/2 - 2 times longer than the calyx-segments, its lobes oblong, obtuse, 1 1/2"-2" long; stigma oval; anthers oblong.
In fields and waste places, southern New York to Pennsylvania, Illinois and Maryland; also in the West Indies. Naturalized from Europe. June-Sept.
Erythraea Douglasii A. Gray, Bot. Cal. 1: 480. 1876.
C. exaltatum W. F. Wight, Contr. Nat. Herb. 11: 449. 1906.
Annual, erect, glabrous, branched, 6-18' high, the branches few, erect, slender. Leaves oblong or linear-oblong, sessile, mostly acute at both ends, 5"-10" long, distant, the basal not tufted; flowers few, terminal and axillary, all slender-pedicelled, 6"-8" long; tube of the corolla about one-third longer than the calyx-segments, the lobes oblong, obtuse, 1 1/2"-2" long.
In sandy soil, western Nebraska to Wyoming, Washington, Arizona and California. May-Sept.
Erythraea texensis Griseb; Hook. Fl. Bor. Am. 2: 58.
1838. C. texense Fernald, Rhodora 10: 54. 1908.
Annual, corymbosely branched above, slender, 2'-8' high. Stem-leaves linear or linear-lanceolate, 8" long or less, acute, sessile, the upper ones reduced to subulate bracts; pedicels slender, as long as the calyx or longer; calyx 4"-5" long, its lobes subulate; corolla light rose color, its tube longer than the calyx, its acute oblong to oblong-lanceolate lobes about half as long as the tube; capsule longer than the calyx.
In rocky soil, Missouri to Texas. May-Sept.
Centaurium calycosum Fernald, Rhodora 10: 54. 1908.
Annual, corymbosely branched or sometimes simple, 2° high or less, the branches ascending or spreading. Leaves oblong to spatulate or linear, 1/2'- 1 1/2' long, acute, sessile; pedicels as long as the calyx or longer; calyx .4,"-$" long, its lobes narrowly linear; corolla pink, its tube a little longer than the calyx, its oval or oblong obtuse lobes nearly as long as the tube.
In wet or moist soil, Missouri to Texas, Mexico and New Mexico. April-June.