Photo of Ivar Tidestron

Ivar was born September 13, 1856, on his father's estate "Lanna" in Hidinge parish, Närke (or Nerike) province, Sweden, near Örebo where he went to school. In 1880, he ran away and came to New York, where all his luggage unfortunately was stolen. He served in the U.S. Army 4th Cavalry from 1880 to 1884 until he injured his hip in a fall from a horse, but served again from 1887 to 1891. In 1891, he began studying engineering at the University of California, but became an assistant to Edward Lee Greene and switched to a botany major. When Greene accepted a professorship at Catholic University in Washington, D.C., Ivar came along and got a PhD degree in 1897. In 1903, he became assistant botanist ($40 per month) in the Bureau of Plant Industry under botanist Frederick V. Coville.

His first major publication, Elysium Marianum (1906-10), a beginning of a flora of Maryland, was illustrated with photos, typeset, and published by him. In 1910, Professor Greene, then an associate in botany at the Smithsonian, had a salary ($1200 per year) paid by the Forest Service to identify all range plants then being collected, with the exception of grasses and sedges. Shortly before Greene's death in 1915, Ivar took over the identification chores and began working on keys for western state floras. In connection with this he collected widely in the western United States. He published his best known work in 1925, Flora of Utah and Nevada.

He retired from the U.S.Department of Agriculture in 1924, at that time probably with the greatest first-hand knowledge of the flora of the United States of anyone. He served five more years in the Botany Department at Catholic University and retired to Florida in 1931 at the age of 75. His later, larger work, Flora of Arizona and New Mexico (1941) was written jointly with Sister [Mary] Teresita Kittell. His last trip to a family reunion in Sweden, made in 1954 when he was 90 years old, resulted in 300 new collections that were added to some 14,000 already deposited at the Smithsonian. He died on August 2, 1956, in St. Petersburg, Florida. A generic name, Tidestromia Standley (Amaranthaceae) and a number of species names, such as Penstemon tidestromii Pennell and Viola tidestromii Greene, commemorate him.

He was elected to the Washington Biologists' Field Club in 1910 and terminated his membership in 1946 for personal reasons.