The binary stars of the water lily world: Nymphaea 'Sirius A' and N. 'Sirius B'

This study introduces Nymphaea 'Sirius A' and 'Sirius B', two new interspecific hybrid cultivars that mirror a binary star system. Developed through hybridization between Nymphaea caerulea and the miniature species Nymphaea thermarum, these 'sister' cultivars share distinct stellate flowers and white petals suffused with pale blue-purple tips. Despite their shared origins and similar morphology, they exhibit distinct dimensional variations. 'Sirius A' is larger, featuring 6–7 cm blooms rising 11–13 cm above the water, while 'Sirius B' is significantly more compact (flower diameter 3–4 cm), with darker olive-green foliage. Both cultivars successfully integrate the dwarf traits of N. thermarum with superior ornamental characteristics, offering novel, compact options for tropical water lily markets.