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..
Biennial or perennial, erect usually branched, somewhat succulent herbs, with slender fleshy tap-roots, alternate entire linear-lanceolate long-acuminate leaves, clasping at the base, and long-peduncled large heads of yellow or purple flowers, opening in the early morning, usually closed by noon. Involucre cylindric or narrowly campanulate, its bracts in 1 series, nearly equal, acuminate, united at the base. Rays truncate and 5-toothed at the apex. Anthers sagittate at the base. Style-branches slender. Achenes linear, terete, or 5-angled, 5-10-ribbed, terminated by slender beaks, or the outermost beakless. Pappus-bristles in 1 series, plumose, connate at the base, the plume-branches interwebbed. [Greek, goats-beard.]
About 35 species, natives of the Old World. Type species: Tragopogon pratensis L.
Flowers yellow: involucral bracts equalling or shorter than the rays.
1. T. pratensis.
Flowers purple; involucral bracts much longer than the rays.
2. T. porrifolius.
Tragopogon pratensis L. Sp. Pl. 789. 1753.
Stem branched, 1 1/2°-3° high. Leaves keeled, tapering from the broad, more or less clasping base to a very long acuminate tip, the lower sometimes 10' long and 1' wide; peduncles thickened at the top; heads 1'-2 1/2' broad; bracts of the involucre about 8, lanceolate, acuminate, shorter than or equalling (rarely exceeding) the yellow rays; marginal achenes striate, smooth or roughened.
In fields and waste places, Nova Scotia to New Jersey, Ontario, Ohio, Manitoba and Colorado. Naturalized from Europe. June-Oct. Called also buck's-beard, noon-flower, star-of-jerusalem, noontide, Joseph's flower, go-to-bed-at-noon.
Tragopogon porrifolius L. Sp. Pl. 789. 1753.
Taller, sometimes 41/2° high. Peduncles very much thickened and hollow for 1 to 3 inches below the heads; heads 2'-4' broad, very showy; bracts of the involucre linear-lanceolate, acuminate, usually much longer than the purple rays; achenes sometimes 2' long, the outer ones covered with scale-like tubercles, especially on the ribs below.
In fields and waste places, Ontario to New Jersey, Virginia, Minnesota, British Columbia, Nebraska and California, mostly escaped from gardens, where it is common. Native of Europe. Called also vegetable oyster, jerusalem-star, nap-at-noon, oyster-root. Naturalized as a weed on the Pacific Coast. The root is the familiar vegetable known as oyster-plant. An apparent hybrid between this and the preceding species has been noticed at New Brunswick, N. J. June-Oct.