It is very important to remove flowers from Waterlilies and Lotus as we do not want new seedlings falling into the water and growing. No hybrids even crossed with only itself will become the same plant from seed. This is the reason we (and most all credible lotus and waterlily growers) do not sell seed. Only species crossed within themselves will produce a replicated plant. Our waterlilies and lotus are grown only from tuber or rhizome root division so that each plant is identical and true to name.
Most marginals are also by root division, some like out canna's, taro, and a few others come from tissue culture facilities. This can be due to costs, or mostly in the canna's favor to prevent an disease from entering the nurseries. in the late 1990s and early 2000s the world was ravaged by one or more canna virus and now the only way to be sure the plants are healthy and disease free is to buy from a nursery like ours where the plants are indexed virus free from the tissue culture labs. Tissue culture has saved many species in the last few years in the plant world.