BioStor
 | Figures of flowering cacteæ, edited by Pfeiffer and Otto; with German and French descriptions. Vol. i. 1843; Vol. ii. Nos. 31 & 32, 1846 (1846) Annals And Magazine of Natural History 18: 275-275 |
 | A list and index of the publications of the United States National Museum (1875–1946) Anon (1947) Bulletin of the United States National Museum 193: 1-306 |
 | ∑Miocene fossil woods from the Columbia basalts of Central Washington. J. Arnold Arb. 42: 165--203. U & E S Barghoorn Prakash (1961) Journal of the Arnold Arboretum 42: 165-203 |
 | Systematic Anatomy and Phylogeny of Mexican Columnar Cacti Arthur C Gibson and Karl E Horak (1978) Annals of the Missouri Botanical Garden 65: 999-1057 |
 | The genera of Phytolaccaceae in the southeastern United States G K Rogers (1985) Journal of the Arnold Arboretum 66: 1-37 |