The goldenaster genus Bradburia Torr. & A. Gray (Asteraceae: Astereae) includes two annual species native to eastern Texas and states to the north and east. Bradburia hirtella Torr. & Gray also has been reported from Louisiana. Bradburia pilosa (Nutt.) Semple [syn: Chrysopsis pilosa Nutt.] is common from central Texas to southwestern Missouri. The treatment here follows Flora North America (Semple 2006 FNA).
Nesom (1991) placed both species in Chrysopsis, while Semple (1996) transferred C. pilosa to Bradburia. In a cladistic study of the Chrysopsidinae, the two species of Bradburia always formed a clade that was never the sister group to Chrysopsis (Semple & Tebby, 1999. A cladistic analysis of subtribe Chrysopsidinae (Asteraceae: Astereae). XVI International Botanical Congress, August 1-7, 1999. St. Louis, Missouri. Abstract No. 2852; Poster No. 401.). In most analyses, the Bradburia clade was sister group or part of the clade with Heterotheca and Croptilon. Recent DNA work indicates Bradburia is more closely related to Chrysopsis (Brouillet et al. 2009), but differs in pappus characteristics (Semple 2006b).
Only the ray florets of Bradburia hirtella produce achenes, which are not well adapted to long distance dispersal. The species is restricted to a narrow range. In B. pilosa, both the rays and discs produce achenes adapted to long distance dispersal.
Semple, J.C. 2006. Bradburia Torrey & A. Gray. pp. 211-212. In Flora North America Editorial Committee, eds. Flora of North America. Vol. 20. Asteraceae, Part 2. Astereae and Senecioneae. Oxford University Press, New York.
Semple, J.C. 2006b. Quadruple, triple, double, and simple pappi in the goldenasters, subtribe Chrysopsidinae (Asteraceae: Astereae). Sida 22 (1): 503-531.
Brouillet, L., T. Lowrey, L. Urbatsch, V. Karaman-Castro, G. Sancho, S. Wagstaff, and J.C. Semple. 2009. Chapter 37. Astereae. Pp. 449-490. In Systematics, Evolution and Biogeography of the Compositae, Funk, V.A., A. Susanna, T. Stuessy, and R. Bayer (eds.). IAPT, Vienna, Austria.
Last revised 26 May 2013 by J.C. Semple
© 2013 J.C. Semple, including all photographs unless otherwise indicated