References:

http://fwie.fw.vt.edu/www/esis/lists/e702030.htm

http://www.tpwd.state.tx.us/nature/endang/ashy.htm

http://www.sanbenito.k12.tx.us/schools/miller%20jordan/science/plants/dogweed.html

http://ifw2es.fws.gov/EndangeredSpecies/lists/SpeciesDetail.cfm?sppcode=7.0

http://www.csdl.tamu.edu/flora/cgi/vpt_m…lla+tephroleuca%3c/i%3e+(blake)+Strother

http://www.csdl.tamu.edu/FLORA/cgi/endemics_map_page2?fam=ASTERACEAE

http://www.csdl.tamu.edu/FLORA/cgi/endemics_map_page2?gen=Thymophylla

http://www.csdl.tamu.edu/FLORA/cgi/endemics_map_page2?gen=Thymophylla&spec=tephroleuca