Powell , A. Michael, Shirley A. Powell, and Chris Jackson. 2017. “Documented Chromosome Numbers 2017:1. Miscellaneous Counts Mostly from Western Texas (U.S.A.), One Each from New Mexico (U.S.A.) and Mexico”. Journal of the Botanical Research Institute of Texas 11 (1):143-46. https://doi.org/10.17348/jbrit.v11.i1.1145.