References
For Cassia
Irwin, H.S., and R.C. Barneby. 1982. The American Cassiinae: a synoptical revision of Leguminosae tribe Cassieae subtribe Cassiinae in the New World. Memoirs N.Y. Bot. Gard. 35: 1-918. Google Scholar
Isely, D. 1975. Leguminosae of the United States. II. Subfamily Caesalpinioideae. Memoirs N.Y. Bot. Gard. 25: 1-228. Google Scholar