The biology of Canadian weeds. 110. Tragopogon dubius Scop., Tragopogon pratensis L., and Tragopogon porrifolius L.

Abstract

Several types of salsify or goat's-beard, Tragopogon species (Asteraceae), are found in Canada as biennial or monocarpic perennial herbs with yellow or purple flowers. Introduced from Eurasia, T. pratensis and T. dubius have become established in all provinces in Canada except Newfoundland and the territories. Tragopogon porrifolius tends to be more local, but is also found in southern areas of most provinces. Tragopogon species hybridize readily, and the tetraploid species T. mirus and T. miscellus have resulted from crosses among the three diploid Tragopogon species in North America. Salsify species produce relatively large umbrella-like pappuses which promote long-distance dispersal. These species also invade rangeland, and are considered noxious weeds in some parts of Canada. Key words: Tragopogon dubius, Tragopogon pratensis, Tragopogon porrifolius, Tragopogon mirus, Tragopogon miscellus, salsify, goat's-beard, Asteraceae, Compositae, hybridization, weed biology