Cyril Marsden has written:

'Rebutia, including Aylostera and Sulcorebutia'

'Mammillaria' -- subject(s): Mammillaria (Cactus)

'Solvents and allied substances manual, with solubility chart'

* Ramonda * Ranunculus (buttercup, crowfoot) * Ranzania * Raoulia * Raphia (raffia) * Ratibida * Ravenala (traveler's tree) * Rebutia * Rehderodendron * Rehmannia * Reineckia * Reinwardtia * Reseda (Mignonette) * Retama * Rhamnus * Rhaphidophora * Rhaphiolepis * Rhapidophyllum (needle palm) * Rhapis (lady palm) * Rheum (rhubarb) * Rhexia* Rhipsalis * Rhodanthe (strawflower) * Rhodanthemum * Rhodiola * Rhodochiton * Rhododendron * Rhodohypoxis * Rhodophiala * Rhodothamnus * Rhodotypos * Rhoeo * Rhoicissus * Rhombophyllum * Rhus (sumac) * Rhynchelytrum * Rhynchostylis (an orchid genus) * Ribes (currant) * Richea * Ricinus (castor-oil plant) * Rigidella * Robinia * Rochea * Rodgersia * Rodriguezia * Rohdea * Romanzoffia * Romneya (Matilija poppy, tree poppy) * Romulea * Rondeletia * Rosa (rose) * Roscoea * Rosmarinus (rosemary) * Rossioglossum * Rothmannia * Roystonea (royal palm) * Rubus (raspberry) * Rudbeckia (coneflower) * Ruellia * Rumex (dock) * Rumohra * Rupicapnos * Ruschia * Ruscus * Russelia * Ruta (rue)