References

For Cirsium

Cronquist, A. 1980. Asteraceae, Volume I, Vascular flora of the Southeastern United States. University of North Carolina Press, Chapel Hill, N.C. Google Scholar

Keil, D.J. 2006f. Cirsium. In Flora of North America Editorial Committee. 2006a. Flora of North America north of Mexico. Volume 19, Magnoliophyta: Asteridae, part 6: Asteraceae, part 1. Oxford Univ. Press, New York, NY. 579 pp. Google Scholar

Nesom, G.L. 2021i. Cirsium ochrocentrum var. martinii (Asteraceae) at specific rank but with an earlier epithet. Phytoneuron 2021-72: 1-22. Published 30 December 2021. ISSN 2153 733X Google Scholar

Nesom, G.L. 2022a. New species of Cirsium (Asteraceae: Cardueae) from Mexico. Phytoneuron 2022-24: 1-100. Published 27 February 2022. ISSN 2153 733X Google Scholar