Tragopogon dubius goat’s beard Asteraceae TRDU*; Q, fr, j, tl; K, pl; R, sb;


Tragopogon dubius.Howard F.

Tragopogon dubius.Howard F. (Accessed 4/2014).

Tragopogon dubius is a biennial herb, 30-100 cm tall, from a taproot, sap milky. 

Leaves alternate, entire, long, slender, basal rosette leaves grass-like, erect, blade tapering from base to tip, clasping stem, young leaves covered with long, wooly hairs, older leaves hairy in axils. 

Flowers pale yellow, in heads 5 cm wide, all rays (ligulate), bracts in one series, few, 13-8, 3-4 cm long, longer than flower rays, stalks widened and hollow below head; self-fertile (autogamous), (Mulligan and Kevan 1973), but visited by insects. flower heads tend to track the sun in the morning and close in the afternoon; blooms May-July; flowering stalks 2-14 per plant; flower heads, one per stalk. 

Fruit an achene 2.5-3.6 cm long including stout beak, with white plume, fruiting head forms a dandelion-like sphere, 7-10 cm diam., bracts about 5-6 cm in seed; one plant produces an average of 90 seeds; seeds wind dispersed up to 250 m; seeds do not require light to germinate and therefore do not form a persistent seed bank (Clements et al. 1999). 

Wetland status: NL. 

Frequency in NYC: Infrequent. 

Origin: Eurasia. 

Habitat: Dry open areas, sandy fill. 

Notes: Leaves and roots edible before plant flowers. Deer, squirrels and rabbits eat flowers. Inflorescences eaten by fruit flies (Tephritiae) and thrips (Thysanoptera) (Clements et al. 1999).