Marshall Conring Johnston (born May 10, 1930) was an American botanist who made several explorations in Mexico and specialized in plants in the family Gesneriaceae.
Johnston was born in San Antonio in the family of Theodore Harris Johnston and Lucille Marie Conringia. He went on his first botanical expeditions to Mexico while still in high school during 1945-1947. On those trips he visited the northern Mexican states of Tamaulipas, Nuevo Leon, Coahuila, Durango, and Zacatecas. From 1972-1974 he made trips to Chihuahua, concentrating on desert flora. These early 1970s trips resulted in the bulk of his botanic collection. Marshal participated in the creation of the books Flora of Texas, Flora of North America, and Flora Neotropica. Johnston was also a professor at the University of Texas at Austin.
Marshalljohnstonia (genus), Henrickson, 1976
Colubrina johnstonii, T.Wendt, 1983
Crataegus johnstonii, J.B.Phipps, 1997
Euphorbia johnstonii, Mayfield, 1991
Frankenia johnstonii, Correll, 1966
Hedeoma johnstonii, R.S.Irving, 1977
Karwinskia johnstonii, R.Fernández, 1988
Matelea johnstonii, Shinners, 1964
Nerisyrenia johnstonii, J.D.Bacon, 1978
Phacelia marshall-johnstonii, N.D.Atwood & Pinkava, 1977
Portulaca johnstonii, Henrickson, 1981
Correll, D. S.; Johnston, M. C. (1970). Manual of the Vascular Plants of Texas. College Station, TX: Texas Research Foundation.
Cheatham, Scooter; Johnston, M. C.; Marshall, Lynn (1995). The Useful Wild Plants of Texas, the Southeastern and Southwestern United States, the Southern Plains, and Northern Mexico. Austin, TX: Useful Wild Plants Inc. ISBN 978-1-8872-9201-6.
Johnston, L. A.; Johnston, M. C. (1999). Rhamnus. New York: New York Botanical Garden. ISBN 978-0-8932-7209-8.
