1 Mediterranean Botany 43, e72561, 2022 From Tropical Flora to Neotropical Flora: José Cuatrecasas and his botanical works José María López Sánchez 1 Received: 17 November 2020 / Accepted: 29 September 2021 / Published online: 21 February 2022 Abstract. The aim of this article is to present the life and professional trajectory of José Cuatrecasas Arumí (1903– 1996), one of the 20th century’s most important Spanish botanists. Therefore, this is a historical study that intends to link the historical circumstances Cuatrecasas experienced with his training as a botanist. This Catalan botanist developed his work in various settings (Barcelona, Madrid, Geneva, Berlin) from his early studies to his doctorate and postdoctoral training, but he began to take an interest in tropical flora from the late 1920s and, more importantly, from the 1930s onwards, when he obtained a chair of botany at the Facultad de Farmacia of the Universidad de Madrid and also became part of the Real Jardín Botánico of Madrid by directing its Tropical Flora Section. The Civil War permanently disrupted the development of his scientific career in Spain, as his Republican militancy forced him into exile. Initially in Colombia and later in the United States, Cuatrecasas continued his lines of research on tropical flora, completing them in the 1960s with an ambitious project in the field of Neotropical Flora. This is how the life and scientific curriculum of one of the best Spanish botanists of the 20th century was forged. Keywords: José Cuatrecasas, Royal Botanical Garden of Madrid, Tropical Flora, Neotropical Flora, history of botany. How to cite: López Sánchez, J.M. 2022. From Tropical Flora to Neotropical Flora: José Cuatrecasas and his botanical works. Mediterr. Bot. 43, e72561. https://doi.org/10.5209/mbot.72561 1 Modern and Contemporary History, Geography and History Faculty, Complutense University of Madrid. Profesor Aranguren s/n, Ciudad Univer- sitaria, E-28040 Madrid. Email: jmlopezs@ghis.ucm.es 2 This work has been conducted within the framework of research project PR65/19-22409. Mediterranean Botany ISSNe 2603-9109 https://doi.org/10.5209/mbot.72561 ARTICLES Introduction 2 Some of the most outstanding episodes of the history of Spanish botany in the 20th century have been infuenced by the fgure of José Cuatrecasas Arumí, whose scientifc career began to focus on tropical botany from the 1930s onwards and who, after the Spanish Civil War, continued a line of research enhanced by his exile in Colombia and the United States, where he was the driver and head of a Commission for the study of Neotropical Flora. The life story and scientifc development of this botanist would be impossible to understand without going back to his origins and the circumstances in which his subsequent career took shape. During the frst third of the 20th century, what is known as the ‘Silver Age of Spanish Science’ developed -an appellation that refers to the most brilliant period that science in Spain had experienced until then. The Junta para la Ampliación de Estudios e Investigaciones Científcas (JAE) took the lead, a state institution created in 1907 to implement a scientifc policy intended both to train new generations of scientists and to found research institutes and laboratories according to the most modern parameters in each scientifc discipline. Except for a few illustrious examples, such as Santiago Ramón y Cajal, Spanish science was, around the turn of the century, prey to all the vices that could cause it to fall behind. The Spanish university system had remained far from experimentation, and out of touch with the most modern currents of scientifc research and, thus, was anchored to outdated budgets that had prevented its renewal throughout the 19th century. Outside the university, there was also a lack of institutions with a distinct vocation for scientifc research that would compensate for its defciencies. This situation delayed the emergence and consolidation of research teams when science had reached cruising speed and was no longer the product of layman’s ingenuity, but of common efforts. To make matters worse, the meager resources of the Ministerio de Fomento, who had taken on these responsibilities during the 19th century, sentenced Spanish science to a situation of underfunding (Otero Carvajal, 2017). This situation began to take a new direction in 1900 with the creation of the Ministerio de Instrucción Pública, whose frst measures were the reform of university curricula to include research, the promotion of “foreign pensions” and the foundation of the JAE so that it could administer the new scientifc policy. The Junta managed to achieve its goals thanks to two basic tools: on the one hand, the pensions or grants for furthering studies in foreign institutions, where young Spanish scientists could access the most signifcant advances and innovations in their disciplines, and on the other hand, the strengthening or establishment within the country of