| Kenneth K. Mackenzie |
Pteridophytes; Spermatophytes; Cyperaceae; Carex; Bryophytes |
| John Macoun |
All groups; Algae; Bryophytes; Mycology; Spermatophytes |
| Bassett Maguire |
Algae; Bryophytes; Pteridophytes; Spermatophytes; Lichens |
| Alfred J. McClatchie |
Algae; Bryophytes; Mycology; Spermatophytes |
| 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 |
| Harold N. Moldenke |
Spermatophytes; Bryophytes |
| Scott Alan Mori |
Lecythidaceae; Spermatophytes; Floristics of neotropical plants; bats and plants; Bryophytes; Lichens |
| Thomas Morong |
Algae; Spermatophytes; Mycology; Bryophytes |
| 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 |
| John S. Newberry |
Fossils; Spermatophytes |
| George E. Nichols |
Bryophytes; Spermatophytes |
| Alice M. Ottley |
Spermatophytes |
| Matthew Charles Pace |
Orchidaceae; Spermatophytes |
| Edward Palmer |
Algae; Bryophytes; Spermatophytes |
| Charles C. Parry |
Algae; Bryophytes; Spermatophytes |
| Paola Pedraza-Peñalosa |
Colombian plants; Ericaceae; Andes; Spermatophytes |
| Francis W. Pennell |
Spermatophytes; Scrophulariaceae |
| Ann P. Pinzl |
Spermatophytes |
| Ghillean T. Prance |
Spermatophytes; Chrysobalanaceae; Bryophytes; Lichens |
| Cyrus G. Pringle |
Algae; Bryophytes; Mycology; Spermatophytes |
| Paul L. Redfearn, Jr. |
Bryophytes; Spermatophytes |
| Clyde F. Reed |
Algae; Bryophytes; Pteridophytes; Spermatophytes; Lichens |
| Padre Raulino Reitz |
Spermatophytes |
| Ludwig Riedel |
Spermatophytes |
| Joseph N. Rose |
Algae; Bryophytes; Cactaceae; Ferns; Fungi; Spermatophytes |
| Henry H. Rusby |
Algae; Spermatophytes; Bryophytes; Lichens |
| Per Axel Rydberg |
Algae; Bryophytes; Mycology; Phanerogams; Pteridophytes; Spermatophytes |
| Sergio C. de Sant'Ana |
Spermatophytes |
| Henry P. Sartwell |
Spermatophytes; Cyperaceae; Bryophytes; Algae; Characeae |
| Arthur C. V. Schott |
Algae; Bryophytes; Spermatophytes |
| George W. Scotter |
Spermatophytes; Bryophytes; Lichens |
| John A. Shafer |
Algae; Pteridophytes; Spermatophytes; Mycology; Bryophytes |
| Aaron J. Sharp |
Algae; Bryophytes; Mycology; Spermatophytes |
| Carleton A. Shurtleff |
Spermatophytes |
| Marcos Silveira |
Spermatophytes; Ecology of arborescent bamboos; systematic botany, plant ecology; flora of Southwestern Amazonia |
| John Kunkel Small |
Algae; Bryophytes; Pteridophytes; Spermatophytes; Lichens |
| Lyman B. Smith |
Spermatophytes; Pteridophytes; Lichens |
| Herbert H. Smith |
Spermatophytes; Bryophytes; Lichens |
| Albert C. Smith |
Algae; Spermatophytes; Pteridophytes; Bryophytes; Lichens |
| Richard Spruce |
Bryophytes; Pteridophytes; Spermatophytes; Lichens |
| Howard Stansbury |
Spermatophytes |
| Julian A. Steyermark |
Pteridophytes; Spermatophytes; Angiosperms; Bombacaceae; Bryophytes; Algae; Characeae; Lichens |
| Arlow B. Stout |
Bryophytes; Spermatophytes; Hemerocallis |
| William C. Sturgis |
Algae; Cryptogams; Mycology; Bryophytes; Spermatophytes |
| William S. Sullivant |
Bryophytes; Algae; Mosses; Spermatophytes |
| David R. Sumstine |
Algae; Mycology; Spermatophytes |
| George H. H. Tate |
Mammology; Spermatophytes; Bryophytes; Lichens |
| Benjamin C. Tharp |
Algae; Mycology; Spermatophytes |
| William Wayt Thomas |
Cyperaceae; Simaroubaceae; Spermatophytes; Bryophytes; Lichens |
| Arnold Gerard Tiehm |
Spermatophytes |
| Benjamin Marland Torke |
Spermatophytes; Swartzia (Fabaceae); Salvia |
| Raymond H. Torrey |
Spermatophytes; Bryophytes; Lichens |
| John Torrey |
Algae; Bryophytes; Euphorbiaceae; Mycology; Pteridophytes; Spermatophytes |
| Erin Anne Tripp |
Acanthaceae; Algae; Bryophytes; Lichens; Spermatophytes |
| Edward Tuckerman |
Mycology; Pteridophytes; Spermatophytes; Lichens; Bryophytes |
| Lucien M. Underwood |
Algae; Bryophytes; Mycology; Pteridophytes; Spermatophytes |
| Anna M. Vail |
Leguminosae; Asclepiadaceae; Spermatophytes; Characeae; Bryophytes |
| Arthur C. Waghorne |
Spermatophytes; Bryophytes; Lichens |
| Jay B. Walker |
Spermatophytes; Lamiaceae |
| Sereno Watson |
Algae; Bryophytes; Euphorbiaceae; Pteridophytes; Spermatophytes; Clarence King Expedition |
| Winona H. Welch |
Algae; Bryophytes; Spermatophytes; Lichens |
| Stanley L. Welsh |
Spermatophytes |
| Margaret J. Williams |
Spermatophytes |
| Robert Statham Williams |
Lichens; Bryophytes; Spermatophytes |
| Percy Wilson |
Algae; Mycology; Spermatophytes; Bryophytes; Lichens |
| Alphonso W. Wood |
Pteridophytes; Spermatophytes |