Rotundifolia vera requires research.
Royalty requires research.
rubra (Aiton) Willd. is a synonym of indica var. indica.
Canna 'Rubra Nerva' is a medium-sized Foliage Group cultivar, with dark leaves and red flowers.
Canna 'Rubra Perfecta' is a medium-sized Foliage Group cultivar, with dark leaves and red flowers.
Canna 'Rubra Superbissima' is a tall Foliage Group cultivar, with dark leaves and red flowers.
Rubricaulis requires research.
rubricaulis Link is a synonym of indica var. indica.
Canna 'Ruby Cole' is a small Crozy Group cultivar, with green leaves and pink flowers.
Ruby Crout requires research.
Russian Lance is a synonym of Rubra nerva.
Canna 'Russian Red' is a tall Foliage Group cultivar, with dark leaves and red flowers.