| Alfred J. McClatchie |
Algae; Bryophytes; Mycology; Spermatophytes |
| Herbert A. McCullough |
Mycology; Lichens |
| Ronald Leighton McGregor |
Algae; Bryophytes; Spermatophytes |
| Gary L. Smith Merrill |
Bryophytes; Spermatophytes; Polytrichaceae |
| Elmer Drew Merrill |
Algae; Bryophytes; Mycology; Pteridophytes; Spermatophytes; Lichens |
| Fabián Armando Michelangeli |
Spermatophytes; Melastomataceae; Tococa |
| John T. Mickel |
Pteridophytes; Spermatophytes |
| Orson K. Miller |
Mycology |
| Harold N. Moldenke |
Spermatophytes; Bryophytes |
| Robbin C. Moran |
Pteridophytes |
| Scott Alan Mori |
Lecythidaceae; Spermatophytes; Floristics of neotropical plants; bats and plants; Bryophytes; Lichens |
| Thomas Morong |
Algae; Spermatophytes; Mycology; Bryophytes |
| Gregory M. Mueller |
Mycology |
| William Alphonso Murrill |
Algae; Cryptogams; Mycology; Spermatophytes; Phanerogams; Lichens |
| Robert Francis Cox Naczi |
Cyperaceae; Sarraceniaceae; North American flora; Spermatophytes |
| George V. Nash |
Spermatophytes; Lichens |
| Michael Harley Nee |
Spermatophytes; Solanaceae; Cucurbitaceae; Phanerogams; Bryophytes; Asteraceae; Lichens |
| Elizabeth J. Neese |
Algae; Scrophulariaceae; Spermatophytes |
| Aven Nelson |
Algae; Mycology; Pteridophytes; Spermatophytes |
| Maria Alice Neves |
Mycology |
| John S. Newberry |
Fossils; Spermatophytes |
| George E. Nichols |
Bryophytes; Spermatophytes |
| Daniel Howard Norris |
Bryophytes |
| Margaret E. Oldenburg |
Bryophytes |
| Todd W. Osmundson |
Mycology |