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..
Linum virginianum var. floridanum(?) Planch. Lond.
1887. Cathartolinum floridanum Small, N. A. Fl. 251: 72. 1907.
Perennial, glabrous, stem strict, stiff, terete, 1 1/2°-2 1/2° high, corymbosely branched above, the branches erect-ascending, slightly angled. Leaves acute, the lowest mostly opposite, narrowly oblong or oblanceolate, the others linear-lanceolate, appressed-ascending, alternate, 5"-10" long, ¥'-2" wide; fruiting branches erect-ascending; fruiting pedicels shorter than or little exceeding the calyx, or the lowest ones slightly longer; sepals ovate, acute or acuminate, about equalling the capsule; capsule ovoid, about 1 1/2" long; petals yellow, twice as long as the calyx.
Eastern Massachusetts and Illinois to Florida and Louisiana. June-Aug.
The plant of the Atlantic Coast, from Massachusetts to Georgia, has somewhat smaller flowers and capsules than the Florida type, and has recently been described as distinct from it as Linum intercursum Bicknell.
Linum catharticum L. Sp. Pl. 281. 1753.
Cathartolinum catharticum Small, N. A. Fl. 251: 74. 1907.
Annual, slender, glabrous, usually branched, 3'-8 high. Leaves all opposite sessile, oval or somewhat obovate, entire, 2"-4' long; flowers axillary and terminal, white, 2"-3" broad, on long slender erect or ascending pedicels; sepals lanceolate, acute or acuminate; petals obovate; pod small, globose.
Along low sandy seashore, Pictou, Nova Scotia and in Ontario. Naturalized from Europe where it is abundant on chalky soils. Called also fairy, mountain, mill-mountain, or purging flax. Fairy lint. July-Aug.
Linum sulcatum Riddell, Suppl. Cat. Ohio Pl. 10. 1836. Linum Boottii Planch. Lond. Journ. Bot. 7: 475. 1848. ?Linitm simplex Wood, Bot. & Flor. 66. 1870. Cathartolinum sulcatum Small, N. A. Fl. 251: 78. 1907.
Annual, simple or branched, 1°-2° high. Stem wing-angled and grooved, at least above; leaves alternate, lanceolate or linear, 8"-12" long, 1"-\\" wide, acute or acuminate, 3-nerved, the lower glabrous, the upper smaller and glandular-ciliate, as are the floral bracts and sepals; stipules represented by a pair of small globose dark-colored glands; flowers racemose or corymbose, about 6" broad, yellow; pedicels 1"-4" long; sepals lanceolate, acute, slightly longer than the ovoid, acute, incompletely 10-celled pod; styles separate above the middle; septa of the capsule ciliate.
In dry soil, Ontario to Manitoba, Massachusetts, Georgia, west to Texas, rare near the Atlantic coast. Summer.