George Engelmann : botanical notebook 19 : Asclepiadaceae, Apocynaceae, Oleaceae, Sapotaceae, Primulaceae, Gesneriaceae, Bignoniaceae, Acanthraceae, Verbenaceae, Labiatae, Plantaginaceae 1827-1882 - Engelmann, George, (1870)
https://www.biodiversitylibrary.org/bibliography/138498
Keywords: 1809-1884|1841-1927|Botanical illustration|Engelmann; George; |North America|Plant collecting|Plants|Sargent; Charles Sprague; |