Red-stemmed parrot's feather

Description

Myriophyllum rubricaule, also known as Myriophyllum aquaticum 'Red Stem' or 'Red Stemmed Parrot's Feather', was previously unclearly affiliated but has since been identified as a new species with its specific epithet meaning "red-stemmed". It is closely related to M. aquaticum, but can be distinguished due to molecular data. The emersed leaves of M. rubricaule are smaller and have fewer pinnae compared to the normal form of M. aquaticum, with brown-red stems instead of green. Underwater, the plant's red stem turns dark in moderate light, and its submersed leaves are reddish with fewer spreading leaflets than normal M. aquaticum. It is likely native to South America due to its relationship with M. aquaticum. In aquariums, it requires high light intensity, complete nutrient supply, and CO2 addition for optimal growth, which can be quite rapid and may require pruning.