UNAM – National Autonomous University of Mexico Herbarium

by David Gernandt
Herbario Nacional de México Chief

A Brief History of MEXU
The National Autonomous University of Mexico (Universidad Nacional Autónoma de México; UNAM) is the largest university in Mexico. Its main campus is called University City, located in the Delegation of Coyoacán in southern Mexico City. UNAM has 350,000 enrolled students, including 112,000 at the preparatory level, 205,000 at the undergraduate level, and 30,000 graduate students. Professors and researchers number 40,000, of which 12,000 are full-time.

UNAM traces its history to the Royal and Pontifical University of Mexico (Real y Pontificia Universidad de México), founded by royal decree in 1551 by Charles I of Spain. It was inaugurated as the National University of Mexico (Universidad Nacional de México) on September 22, 1910, thanks in great part to the efforts of the intellectual Justo Sierra Méndez (García Stahl, 1975). In the aftermath of the Mexican Revolution in 1929, the university was given its autonomy from the Secretary of Public Education, resulting in the addition of “Autónoma” to its former name.

The Institute of Biology (Instituto de Biología; IBUNAM) is a research center dedicated to conducting research into the origins, interactions, distribution,  present composition, use, and conservation of Mexico’s biological diversity. It  is one of 33 research institutes at UNAM. The IBUNAM is the custodian of the greater part of Mexico’s National Biological Collections (Colecciones Biológicas Nacionales; CBNs). The Department of Zoology houses   ten   collections: insects, arachnids, mollusks, crustaceans, fish, reptiles and amphibians, helminths, birds, and mammals. The Department of Botany houses the National Herbarium of Mexico (Herbario Nacional de México; MEXU). Currently, the CBNs have more than 3 million catalogued specimens.

MEXU houses 1.5 million catalogued specimens. The vascular plant collection has 1.4 million specimens, including more than 1,200 holotypes and 6,200 isotypes. It is divided into nine halls that are curated by nine academic technicians. MEXU has another four main collections: bryophytes (48,000 specimens), curated by Claudio Delgadillo Moya; fungi (>11,000 specimens), curated by Elvira Aguirre Acosta; lichens (10,000 specimens), curated by Marusa Herrera Campos and Elvira Aguirre Acosta; and algae (5,500 specimens), curated by José Luis Godínez Ortega. MEXU also includes an ethnobotanical collection (>3,600 specimens), curated by Cristina Mapes Sánchez, and a xylarium (3,500 blocks of wood), curated by Josefina Barajas Morales.

The National Herbarium (Herbario Nacional) was created in 1929 as part of the Department of Botany of IBUNAM, but it houses specimens from earlier institutions,   most importantly the National Medical Institute (Instituto Médico Nacional; IMN) and the National Museum (Museo Nacional). The IMN was founded in 1888 during the rule of Porfirio  Díaz.   It occupied temporary sites near the center of Mexico City before it moved to a newly constructed building on the corner of Ayuntamiento and Balderas. The herbarium of the IMN (Fig. 1) held the collections of the Mexican Scientific Commission (Comisión Científica Mexicana, 1883) and the Commission of the Valley of Mexico  (Comisión del Valle de México, 1856).

Among its principal activities, it documented medically useful plants and developed vegetation and other maps for the country. An important work from this time was “Datos para la Materia Médica Mexicana,” published by the founding director, Fernando Altamirano, and José Ramírez in four volumes  from  1894  to  1908.  In  1904,  the  IMN reported 8,000 exsiccata (Alcocer, 1904).

In 1915, in the midst the Mexican Revolution, the IMN became the Directorate of Biological Studies (Dirección de Estudios Biológicos). Its founding director was the evolutionary biologist, Alfonso Luis Herrera. The Directorate absorbed the collections of the IMN, the National Natural History Museum (previously named the National Museum, founded in 1825),   the   Geographic   Exploratory   Commission (Comisión Geográfica Exploradora , 1876), the Museum of Tacubaya (Museo de Tacubaya, 1893), and the Exploratory Commission for Natural  Flora and Fauna (Comisión Exploradora de la Flora y Fauna Naturales, 1907; Ortega et al., 1996).

The first director of the Botanical Section of the Directorate of Biological Studies was Miguel Cordero. Years later the post was held by Maximino Martínez, who adopted the classification of Engler as organized by Dalla Torre y Harms (Cuevas Cardona and López Ramírez, 2009), which is still followed today for flowering plants. In 1925 the herbarium was reported to have 24,387 catalogued specimens comprising almost 8,000 species, and another 40,000 uncatalogued specimens (Herrera, 1925). The Directorate moved to the Casa del Lago, Chapultepec in 1927 (Herrera et al., 1998; Fig. 2). In 1929, the Directorate of Biological Studies, together with its collections, were transferred to the newly established IBUNAM. In 1956, it moved to new installations in University City (Ciudad Universitaria). The IBUNAM has occupied its current building in University City, west of Insurgentes Sur and next to the IBUNAM Botanical Garden since 1999 (Fig. 3).

Documenting the Biological Diversity of Mexico and the Americas
MEXU’s earliest collections predate the Mexican War of Independence (1810–1821) when its territory comprised part of New Spain. Most notable are collections from the Royal Scientific Expedition (Real Expedición Científica) sent by King Carlos III of Spain and lasting from 1787 to 1803. MEXU houses specimens from this expedition collected from Puebla in 1787 by Martín Sessé y Lacasta and José Mariano Mociño. MEXU’s oldest specimen is of Roldana ehrenbergiana (Klatt) H.Rob & Bretell, originally labelled as “Senecio canicida Sp. N.” by Sessé (Fig. 4). MEXU houses bound herbaria (1789 and 1800) from Vicente Cervantes, another participant in the expedition. These specimens are principally of Asteraceae collected around Mexico City. Several hundred specimens in the herbarium were collected prior to the Mexican War of Independence in 1810. Important collectors after the war and up until the beginning of the Mexican Revolution in 1910 included Fernando Altamirano, Gustave Joseph Brouard Arsène, Eugène Bourgeau, Cassiano Conzatti, Eugene Langlassè, Ferdinand J. Lindheimer, Rafael Montes de Oca, Edward Palmer, Antonio Peñafiel, Cyrus G. Pringle, Johann G. Schaffner, and José J. Triana.

A high proportion of MEXU’s earliest collections document the floristic diversity of Mexico City and the surrounding states that make up the Valle de México. This basin has undergone profound changes in its land use, even before Tenochtitlan’s conquest by Hernán Cortés in 1521, when, as the capital of the Aztec’s vast Mesoamerican empire, it was a city of several hundred thousand people surrounded by Lake Texcoco. Today Mexico City is a megalopolis of 21 million people. A recent example of land use change brought on by urbanization is that suffered by the Pedregal de San Ángel, a vast expanse of lava rock preserving a xeric shrubland characterized by Senecio praecox in southern Mexico City. In the first half of the 20th Century, UNAM’s main campus was built on the Pedregal. One of its most laudable floristic treatments was Jerzy Rzedowski’s 1954 publication “Vegetación del Pedregal de San Ángel (Distrito Federal, México)”. Today, 90% of the Pedregal has been developed into neighborhoods, businesses, roads, and even institutions of the UNAM. Much of what is left forms a designated Ecological Reserve of 237 hectares inside University City.

The holotype of Senecio canicidus Sessé & Mociño (a synonym of Roldana ehrenbergiana [Klatt] H.Rob. & Brettell). Collected in Puebla by Sessé and Mociño between 1787 and 1803 and thought to be the oldest specimen in MEXU.

MEXU Today
Among the most specimen-intensive projects currently conducted   at   MEXU   are   the   determinations   of botanical collections for  the National Inventory  of Forests and Soils (Inventario Nacional Forestal y de Suelos), DNA barcoding, and large-scale digitalization of the National Biological Collections. Martin Ricker of the Department of Botany has led several projects to verify  determinations of Mexico’s National Inventory of    Forests and Soils. The inventories  are  carried  out  by  the National              Forestry Commission (Comisión Nacional Forestal; CONAFOR) in order to document forest distribution, composition, and demography,  and  to  plan  for  the  sustainable  use  of  forest resources. Approximately 10,000 collections per year enter the herbarium for determination, of which 10–20% are selected for accession. The determinations are made by MEXU personnel, mainly Esteban Martínez Salas, and botanists paid from the projects. The sampling design requires collections to include remote localities, and also include tissue samples in silica gel for future DNA barcoding studies (tissue and DNA collections are currently maintained by individual researchers) and wood cores for dendrochronological analyses.

MEXU has participated in a number of floristic studies over the years. The IBUNAM supports institutional projects such as the Flora Mesoamericana in collaboration with the Missouri Botanical Garden and the Natural History Museum of London This project was coordinated at IBUNAM for 35 years by Mario Sousa Sánchez (Fig. 5), and was taken over in 2017 by Héctor Hernández Macías. Other recent and ongoing studies include the Flora del Valle de Tehuacán-Cuicatlán, and floras of the states of Veracruz and Oaxaca, the municipality of Guadalcázar, San Luis Potosí, and along the overwintering and migration routes of the Monarch butterfly.

A significant proportion of MEXU’s collections are recent. Mexico’s government funded much exploration of biological resources in the 1980’s.    Collection       activity      for MEXU             peaked              at approximately 60,000 specimens in 1985 under the direction of Mario Sousa Sánchez. These collections are an important resource for destructive sampling, most commonly for anatomical and DNA studies. We permit limited tissue sampling in recognition that some species are confined to remote regions that are often difficult to access. Unfortunately, several taxonomic groups, such as those protected by CITES (for example, Cactaceae and Cycadaceae), are becoming intensively sampled in the collection. In other cases, fairly easy-to-collect species are being sampled by researchers wishing to save time and effort, even though the herbarium’s representation of these species is limited.

Ten academic technicians curate MEXU’s collection and oversee its daily operations, including loan and access to type specimens  (Maru García  Peña), exchange (Gilda Ortiz Calderón), donation (Alberto Reyes García), mounting (Laura Calvillo Canadell), plant identification (Verónica Juárez Jaimes), special collections and catalogues (Martha Olvera García), and digitization programs (Angélica Ramírez Roa). The academic technicians also participate in floristic studies (Alberto Reyes García, Esteban Martínez Salas, and Rafael Torres Colín), conduct original research in plant systematics, and teach courses in plant mounting and identification.

Mario Sousa, Herbarium Chief from 1975–1985 and 1994–2003. Photo by Carmen Loyola, 2014.

MEXU also has 12 full-time technicians whose main responsibility is to mount plants. These technicians also prepare new specimen folders, pack and ship specimens for other herbaria, and type and print collection labels. Thanks to their efforts, the number of vascular plants mounted and accessioned per year has ranged from 20,000 to 30,000 in the last decade. In 2017, the technicians began taking digital photographs of newly mounted and recently annotated specimens.

Approximately one-third of MEXU’s specimens have come from exchange with other herbaria and one-tenth from donations. Our main exchange partners are the Missouri Botanical Garden (MO), Royal Botanic Gardens (K), the New York Botanical Garden (NY), Universidad de Guadalajara (IBUG), Instituto de Ecología, A.C. at Xalapa (XAL), and Instituto de Ecología, A.C. at Pátzcuaro (IEB). The remainder of MEXU’s collection has been made by researchers and students at UNAM, principally from the IBUNAM’s Department of Botany and Botanical Garden.

Specimens used for guided tours, Sala Bletia.

MEXU receives visitors from diverse fields, including plant taxonomy, ecology, agriculture, ethnobotany, paleobotany, plant anatomy, medicine, architecture, art, and history. MEXU is consulted by government scientists, such as those from the National Institute of Statistics and Geography (Instituto Nacional de Estadística y Geografía; INEGI). MEXU also opens its doors to the public, offering guided tours both by appointment and during special events to more than 1,000 people per year, mainly students of high schools and undergraduate programs from Mexico City and surrounding states (Fig. 6).

Digitization of MEXU
In 2012, IBUNAM began an ambitious four-year project funded by CONABIO to digitize the National Biological Collections. IBUNAM has been steadily digitizing its collections for decades, mainly focusing on taxonomic groups of interest to its researchers. The accumulated data for that effort, including 288,347 specimens from MEXU, are available on the UNIBIO bioinformatics unit website (Unidad de Informática para la Biodiversidad; http://unibio.unam.mx/). The 2012 project as envisioned by our director, Víctor Sánchez Cordero, was grander than its predecessor, involving centralized data capture for all biological collections with 18 computer terminals, a new database platform, and extensive cleaning of captured specimen data. In June of 2012 digitization began on four collections, including MEXU.

MEXU adopted the system used by the Consortium of Pacific Northwest Herbaria for taking photographs of mounted vascular plants (Legler, 2011). Digital images are taken in Ortery light boxes with a Canon EOS 5D Mark II fitted with a Sigma 50 mm f/2.8 EX DG macro lens. During the four-year project, two to three taxonomic specialists worked full-time selecting, reviewing, stamping, and photographing specimens. The images are saved in jpg format at 3744 by 5616 pixels (21 megapixels) on the internal hard drives of computers connected to the cameras, and backups are made on external 2-3 TB hard drives and then copied to a UNIBIO server.

Workers manually capture label data for the botanical and zoological collections at 18 computer terminals in UNIBIO. The capture screen allows verbatim entry of vascular plant specimen data. The vascular plants are captured from digital images, whereas most other collections, including MEXU’s collections of fruits, seeds, fungi, and lichens, which are in envelopes and boxes, are captured directly from specimen labels rather than from photographs. Digitization of the bryophyte label data was continued independently by Claudio Delgadillo, who has maintained that collection for years.

The specimen database is managed with PostgreSQL and other open source software developed at IBUNAM. After initial data capture, automated data quality protocols are used to verify geographic data, match determinations to taxonomic catalogs, and homogenize names of collectors. UNAM’s rector decided to adopt the system for all of its collections, forming the Coordination of University Digital Collections (CCUD) in 2013. The CCUD database is being steadily made available online at their open data portal (https://datosabiertos.unam.mx/). Currently, 1,195,079 (75%) of the digital objects available online are MEXU specimens.

Based on the 1,195,000 MEXU specimens available on the open data portal, 80.8% are from Mexico, followed by 3.8% from the United States, 1.9% from Guatemala, and 1.4% from Costa Rica. Outside of Mexico our collections come mainly from the United States, followed by Central America, and then South America. Approximately 30% of MEXU’s collections are from Mexico’s three most floristically-diverse states: Oaxaca, Chiapas, and Veracruz. Approximately 37% of the specimens have geographic coordinates.

In 2017, the director of the Instituto de Biología was awarded a one-year project to continue with the digitization of the National Biological Collections. We foresee that this will allow us to complete photography of all vascular plants in the herbarium except those that were sent out on loan before 2012. We invite those who are interested to follow the digitization effort on UNAM’s open data portal.

Acknowledgements – I am indebted to José Luis Godínez for proofreading a previous draft and providing additional invaluable information on  the history of MEXU. I also thank Gilda Ortiz Calderón and Maru García Peña for providing statistics on the vascular plant collection, Gerardo Salazar for reviewing a previous draft, and Carmen Loyola Blanco and María del Socorro Tapia for providing photos from the historical archives of IBUNAM.

Literature Cited
Alcocer, G. 1904. Los herbarios del Instituto Médico Nacional. Lectura de turno (30 junio 1904). Anales del Instituto Médico Nacional, Serie 6, 11: 214–268.

Cuevas Cardona, M. del C. and C. López Ramírez. 2009. Cambios de gobierno en la vida de un botánico mexicano: Maximino Martínez (1888-1964). Historia Mexicana 58: 973–1004.

García Stahl, C. 1975. Síntesis histórica de la Universidad de México. Universidad Nacional Autónoma de México, México, 321 pp.

Herrera, L.A. 1925. Informe compendiado de los trabajos llevados a cabo por la Dirección de Estudios Biológicos (durante el periodo comprendido entre el 1º. de agosto de 1924 y el 31 de julio de 1925. Imprenta de la Dirección de Estudios Biológicos, México, 16 pp.

Herrera, T., M.M. Ortega, J.L. Godínez, and A. Butanda.  1998.  Breve  historia  de  la  botánica  en México. Fondo de Cultura Económica, México D.F. 167 pp.

Legler, B. 2011. Specimen imaging documentation. Consortium of Pacific Northwest Herbaria, ver. 4.0.

Ortega, M.M., and J.L. Godínez Ortega y G. Vilaclara. 1996. Relación histórica de los antecedentes y origen del Instituto de Biología de la Universidad Nacional Autónoma de México. Instituto de Biología, UNAM, México, 97 pp.