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Thomas K. Todsen collection

Identifier: Ms-0223

Scope and Contents

The collection consists of materials collected by Dr. Thomas K. Todsen. Areas of interest to him included Arizona/New Mexico postal history, US postal stamps, postcards and photographs related to New Mexico; letters, receipts, advertisements, and various documents related to New Mexico. The collection is arranged in three series: Papers, Stamp Collection, and Photographs. Papers consist of miscellaneous letters, receipts, articles and other documents related to New Mexico collected by Dr. Todsen. The Stamp Collection consists of United States postage stamps collected by Dr. Todsen. Subjects include notable people, space exploration, Christmas, etc. The Photograph series is the bulk of the collection and primarily consists of postcards, contact prints, and copy negatives. Subjects include the Mexican Revolution, southern and northern New Mexico, national parks, historic landmarks, New Mexico post offices, New Mexico College of Agriculture and Mechanic Arts, etc. The Papers and Photographs series are arranged by accession.


  • 1826 - 1990

Conditions Governing Use

Open. All materials in this collection are available for research under supervised conditions in the Research Room. Researchers should contact the department in advance to make arrangements to view unprocessed materials, as these may need to be screened before use.

Biographical / Historical

Dr. Thomas K. Todsen was born in Pittsfield, Massachusetts on October 21, 1918 to Lorenz K. Todsen and Ellen (Christensen) Todsen. He died on December 22, 2010 in Abilene, Texas. At the age of 12, after his father’s death, the family moved to St. Petersburg, Florida. Dr. Todsen graduated from St. Petersburg High School in 1935 and went on to receive his Bachelor’s and Master’s degrees in chemistry in 1939 and 1941 and his Ph.D. in organic chemistry in 1950, all from the University of Florida. While at the university, Dr. Todsen met his wife Margaret C. Dorsey. They wed on August 4, 1939.

Dr. Todsen enlisted in March 1942 and served as an Army Chemical Warfare Service officer. He was honorably discharged in August 1947 as a Captain. He went on to attain the rank of Major while serving in the Army Active Reserves from 1951-1962. He taught briefly at New Mexico State University before he was hired at White Sands Missile Range as Chief Chemist in 1950. At the time of his retirement from WSMR in 1978, Dr. Todsen was serving as the Director of the Army Missile Test and Evaluation Command.

Dr. Todsen had various interests, including Arizona/New Mexico postal history, the study of orchids and wildflowers, and photography. Several of his photographs appear in Wild Flowers of the United States. He discovered a new species of fossil snail and has a wildflower named after him: Todsen’s pennyroyal (Hedeoma todsenii). He wrote New Mexico Territorial Postmark Catalog and co-wrote The Travelling Post Offices of Mexico. He also authored numerous scientific articles and publications.

Dr. Todsen was a member of the Orchid Society of America, the American Society of Plant Taxonomists, the New Mexico Rare Plant Technical Council, the American Media Photographer’s Association, the Mesilla Valley Stamp Club, the American Chemical Society, American Ordnance Association, and Phi Gamma Delta fraternity. His name has been listed in Who’s Who in the West, American Men of Science, and Dictionary of International Biography.


7.25 Linear Feet

Language of Materials



Dr. Thomas K. Todsen was an avid collector of materials related to New Mexico. His collection consists primarily of postcards depicting New Mexico and the southwest. His collection also contains letters, receipts, and miscellaneous documents related to New Mexico.

Related Materials

Ms 0430 Register of the Mexican Revolution Photographs, ca. 1910-1920, Archives and Special Collections, New Mexico State University Library. Ms 0475 Guide to the Connie Sharpe Postcard Collection, 1903-1912, Archives and Special Collections, New Mexico State University Library.

Processing Information

This collection was processed by Elizabeth Villa (Spring 2019).
Guide to the Thomas K. Todsen collection
Finding aid by Elizabeth Villa
Description rules
Describing Archives: A Content Standard
Language of description
Script of description
Code for undetermined script
Language of description note

Repository Details

Part of the New Mexico State University Library Archives and Special Collections Repository

Branson Hall
PO Box 30006
MSC 3475
Las Cruces New Mexico 88003 USA