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Published In: Species Plantarum 2: 789. 1753. (1 May 1753) (Sp. Pl.) Name publication detailView in BotanicusView in Biodiversity Heritage Library

Project Name Data (Last Modified On 8/11/2017)
Acceptance : Accepted
Project Data     (Last Modified On 7/9/2009)
Status: Introduced


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49. Tragopogon L. (goat’s beard)

Plants mostly biennial herbs (sometimes short-lived perennials), with somewhat fleshy taproots. Latex white. Stems 1 to several, erect or ascending, unbranched or more commonly with ascending branches, often hollow (at least toward the tip), often swollen toward the tip (at least at fruiting), finely ridged, usually with patches of fine, white, cobwebby to woolly hairs when young, appearing glabrous or nearly so at maturity, often glaucous, sometimes purplish-tinged or purplish-mottled around the lower nodes. Leaves basal and alternate, sessile, the basal leaves sometimes withered at flowering. Leaf blades grasslike, unlobed, linear from a slightly broadened, more or less rounded base (this sometimes purplish-tinged), the margins often slightly corrugated or somewhat incurled and with a narrow, pale band, this often slightly and microscopically roughened, the surfaces sometimes with small patches of inconspicuous, cobwebby hairs toward the base when young, appearing glabrous at maturity, usually glaucous. Venation of few to several apparently parallel main veins, sometimes the central main vein somewhat thicker than the others, and a sometimes faint network of anastomosing secondary veins. Heads solitary at the branch tips. Involucre elongating as the fruits mature, conical to bell-shaped at flowering, the bracts in 1 series of 8–13, all similar in size and shape (no shorter outer bracts present), lanceolate to narrowly lanceolate, long-tapered at the tip, usually with a narrow, pale margin, glabrous or cobwebby-hairy at the base, sometimes purplish-tinged. Receptacle naked, but often with minute, scaly ridges between the florets. Ligulate florets 50–180 or more per head. Corollas yellow or purple. Pappus of numerous plumose bristles, these off-white to straw-colored or tan to light brown, a few usually distinctly longer than the rest. Fruits with the body narrowly lanceolate to nearly linear in outline, often somewhat curved or asymmetrical, tapered to a slender or relatively stout beak 1–2 times as long as the body (rarely some of the outermost fruits with a much shorter beak), not or only slightly flattened, with 5–10 nerves or fine, rounded ribs, the surface with dense tubercles or blunt, ascending barbs, straw-colored to tan or dark brown (often varying in color in a single head), the pappus attached to a relatively broad, expanded, disclike tip (except in T. porrifolius, with a narrow, club-shaped tip), this frequently with woolly hairs. About 50 species, Europe, Asia, Africa.

Tragopogon defies conventional definitions of the native vs. nonnative status of species in the North American flora. The three Old World diploid species in Missouri are widely naturalized in temperate North America. Where mixed-species populations occur (first studied in the northwestern United States and not yet noted in Missouri), sterile hybrids are produced frequently. In several independent cases, two of these hybrids have regained their fertility through allopolyploidy (doubling of the chromosomes in an interspecific hybrid), with each tetraploid derivative acting biologically as a full species. This phenomenon in Tragopogon formed the basis for a seminal series of studies in plant biosystematics by Marion Ownbey and his colleagues at Washington State University (Ownbey, 1950; Ownbey and McCollum, 1953, 1954; Belzer and Ownbey, 1971). Since then, Ownbey’s findings on reticulate evolution in the genus have been confirmed and refined by Pamela and Douglas Soltis (then at Washington State University) and their colleagues (Novak et al., 1991; Soltis and Soltis, 1991; Soltis et al., 1995; Cook et al. 1998). Because the two fertile allotetraploid species, T. mirus Ownbey (derived from past hybridization between T. dubius and T. porrifolius) and T. miscellus Ownbey (derived from past hybridization between T. dubius and T. pratensis), have been documented to have evolved during the twentieth century in the western United States (and apparently have not formed in Europe), they have been treated by most authors as natives of North America, even though their progenitors are not native to the continent.

Heads of Tragopogon species open each morning and, except on cloudy days, generally close by noon. The plumose pappus bristles tend to intertwine, and when the involucral bracts become reflexed as the fruits mature, the pappus takes on an intricate globose shape. These fruiting heads are sometimes carefully dried and then sprayed with an aerosol resin (to prevent dispersal of the fruits) for use in dried flower arrangements. Before the heads are produced, plants of Tragopogon might be confused with some monocot genera such as Tradescantia (Commelinaceae) or some grasses. However, the grasslike leaves in Tragopogon do not have sheathing bases as in nearly all monocots.


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1 1. Corollas light purple to bright purple, the tubular basal portion sometimes yellow ... 2. T. PORRIFOLIUS

Tragopogon porrifolius
2 1. Corollas light yellow to bright yellow

3 2. Involucral bracts longer than the florets; stems usually swollen toward the tip ... 1. T. DUBIUS

4 2. Involucral bracts shorter than to as long as the florets; stems not swollen toward the tip at flowering, occasionally becoming slightly inflated at fruiting ... 3. T. PRATENSIS Tragopogon pratensis
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