George Engelmann : botanical notebook 58 : Ephedra and Equisetum - Engelmann, George, (1860)
https://www.biodiversitylibrary.org/bibliography/149702
Keywords: 1805-1877|1809-1884|Botanical illustration|Braun; Alexander; |Engelmann; George; |Ephedra|Ephedraceae|Equisetaceae|Equisetum|North America|Plant collecting|Plants|