Typification of Mexican Euphorbia (Euphorbiaceae) Author Steinmann, Victor W. 0000-0003-0103-9575 Instituto de Ecología, A. C., Centro Regional del Bajío, Av. Lázaro Cárdenas 253, 61600 Pátzcuaro, Michoacán, Mexico. steinmav@gmail.com text Phytotaxa 2023 2023-12-12 630 1 61 68 https://phytotaxa.mapress.com/pt/article/download/phytotaxa.630.1.5/51357 journal article 10.11646/phytotaxa.630.1.5 1179-3163 10361687 Euphorbia elastica Altamirano & Rose (July 1905: 323), nom. illeg. (non E. elastica Jumelle [April] 1905: 1047). ≡ Euphorbia fulva Stapf (1907: 294) . ≡ Euphorbiodendron fulvum (Stapf) Millspaugh (1909: 305) . Lectotype (designated here):— MEXICO . Michoacán : Zamora , June 1905 , F. Altamirano 1539 ( US no. 474882 /barcode 00026666 !; isolectotypes MEXU barcode MEXU00053547 !, MEXU barcode MEXU00160573 !) . Altamirano & Rose’s original publication (1905) contained a detailed morphological description, in English and Spanish, and a pair of photographs of plants in the field. It lacked information about where, when, and by whom it was collected. Shortly thereafter, Altamirano (1905) published an account of the species detailing its distribution and potential as a source of natural rubber. However, no specimens were cited. The only known original material consists of three Altamirano specimens at the herbaria MEXU and US . Of these, the specimen at US is chosen as lectotype . It is the only one that has the information about type locality and date of collection, and it is likely the only specimen seen by Rose. Euphorbia elastica is a synonym of E . tanquahuete Sessé & Moc. , see below.