Railliardia latifolia var. helleri Sherff Unknown
Raimannia colimae Rose Isotype
Ramirezella pringlei Rose Isotype
Randia canescens Greenman Isotype
Ranunculus allenii Robinson Isotype
Ranunculus auricomus ssp. decorifactus E. Julin Isotype
Ranunculus auricomus ssp. hemicyclodon E. Julin Isotype
Ranunculus orthorhynchus var. alaschensis L. D. Benson Isotype
Ranunculus pringlei Briquet Isotype
Ranunculus vagans Watson Isotype
Relbunium mezocarpum Greenman Isotype
Rhamnus pringlei Rose Isotype
Rhexia floridana Nash Isotype
Rhinanthus oblongifolius Fernald Isosyntype
Rhodosciadium dissectum Coulter & Rose Isotype
Rhodosciadium glaucum Rose Isosyntype
Rhus argyi Leveille Isotype
Rhus mairei Leveille
Rhus rhomboidea Small Isotype
Rhynchosia cinerea Nash Isotype
Rhynchosia pringlei J. N. Rose Isotype
Rhynchospora pringlei Greenman Isosyntype
Ribes leucoderme Heller Isotype
Ribes migratorium Suksdorf Isotype
Ribes pringlei Rose Isotype
Ribes rugosum Coville & Rose Isotype
Robinia pringlei Rose Isotype
Robinsonella pilosa ssp. septentrionalis Fryxell Isotype
Roldana subcymosa H. Robinson Isotype
Romanzoffia californica Greene Isotype
Romanzoffia macounii Greene Isotype
Rorippa columbiae Howell Isotype
Rouliniella jaliscana Vail Isolectotype
Ruellia cupheoides Fernald Isotype
Ruellia malacosperma Greenman Isosyntype
Ruellia pringlei Fernald Isotype
Rumex fascicularis Small Isotype
Rumex subalpina Jones Isosyntype
Russelia pringlei B. L. Robinson Isotype
Russelia tepicensis B.L. Robinson Isotype
Russelia trachypleura B. L. Robinson Isotype