By Williams, Louis Otho, 1908- . Genre Scrophylariaceae . Names scrophulariaceae / s f / verbenaceae / schlegelia / bignoniaceae and 102 more

By Williams, Louis Otho, 1908- . Genre nc----- / Botany / Central America / Tropical plants / Central America . Names leaves / type / corolla / flowers / mexico and 945 more

By Williams, Louis Otho, 1908- . Genre n-mx--- / nc----- / Hoffmannia / Botany / Mexico and 2 more . Names corolla / hoffmannia / type / calyx / molina and 250 more

By Williams, Louis Otho, 1908- . Genre Botany / Neotropics . Names america / mexico / type / american / plants and 1700 more

By Standley, Paul Carpenter, 1884-1963 / Williams, Louis Otho, 1908- / Nash, Dorothy L. . Genre ncgt--- / Botany / Guatemala . Names calyx / corolla / leaves / seeds / flowers and 9412 more

By Standley, Paul Carpenter, 1884-1963 / Williams, Louis Otho, 1908- . Genre ncgt--- / Rubiaceae / Guatemala / Botany / Guatemala . Names leaves / corolla / calyx / flowers / mexico and 16991 more

By Standley, Paul Carpenter, 1884-1963 / Williams, Louis Otho, 1908- / Gibson, Dorothy N. . Genre ncgt--- / Botany / Guatemala . Names leaves / corolla / calyx / flowers / mexico and 9601 more

By Williams, Louis Otho, 1908- . Genre nc----- / Botany / Central America / Tropical plants / Central America . Names leaves / corolla / american / flowers / mexico and 690 more

By Williams, Louis Otho, 1908- . Genre n------ / Bignoniaceae / Botany / North America . Names amphitecna / leaves / mexico / type / enallagma and 216 more

By Williams, Louis Otho, 1908- . Genre nc----- / Botany / Central America / Tropical plants / Central America . Names leaves / flowers / american / type / plants and 797 more