References

For Xanthisma

Hartman, R.L. 2006a. Xanthisma. In Flora of North America Editorial Committee. 2006b. Flora of North America north of Mexico. Volume 20, Magnoliophyta: Asteridae, part 6: Asteraceae, part 2. Oxford Univ. Press, New York, NY. 666 pp. Google Scholar

Nesom, G.L. and B.L. Turner. 2007. Taxonomic review of the Xanthisma spinulosum complex (Asteraceae: Asterae). Phytologia 89(3): 371-389. Google Scholar

Semple, J.C. 1974. The phytogeography and systematics of Xanthisma texanum DC. (Asteraceae): proper usage of infraspecific categories. Rhodora 76: 1-19. Google Scholar

Turner, B.L., and R.L. Hartman. 1976. Infraspecific categories of Machaeranthera pinnatifida (Compositae). Wrightia 5: 308-315. Google Scholar