Type specimens collected by Juan Isern during the Pacific Scientific Commission to South America (1862-1866)

Juan Isern collected ca. 25,000 plant specimens during the Pacific Scientific Commission to South America between 1862 and 1866, but unfortunately he died the same year the expedition returned to Spain. In Chile, Isern exchanged specimens with Philippi, who later described three new species based on those collections which are all deposited at SGO. In the early 1930s, Jose Cuatrecasas worked intensively with the Isern collections at MA, where most of lsern's South American specimens are deposited. Cuatrecasas, Trelease, Sleumer, Standley and Yuncker described several new species and other taxa using Isern collections as type material. A total of 47 species, 21 varieties and 7 forms were described in 9 families, principally in the Asteraceae, Piperaceae and Gesneriaceae based on Isern collections. Here, the nomenclature of all Isern type specimens is studied for these 75 names. Lectotype specimens for the names of four species, three varieties and five forms described by Cuatrecasas and one species described by Trelease are designated in the present paper.