The Herbarium of the National Museum (R) of the Department of Botany of the National Museum (Federal University of Rio de Janeiro) was founded in 1831, being the first herbarium in Brazil and one of the largest in Latin America. The herbarium encompasses approximately 500,000 specimens. The algae collection (R-Algae) includes material collected by many foreign naturalists, mainly during the 19th century, covering distinct aquatic environments from Brazil and abroad (e.g. E. Ule, P. von Luetzelburg, Lenormand, Prouet, Rabenhorst collections). The collection R-Algae consists of the 2814 exsiccatae of macroalgae, (2197) and microalgae (617), liquid preserved specimens, especially continental microalgae accounting for a total of 4560 vials, and the diatom Collection comprising of over 80 permanent slides. The R-Algae represents 1,5% of the total of general collection, including 12 types. The collection is organized in compacting cabinets and in alphabetical order and is in good condition. Currently, the material is in the process of informatization. It is an active and continuously growing collection.