The Blue Nile lotus is actually a waterlily (Nymphaea) as illustrated in the wonderful old botanical painting. And when Homer wrote of "land of the lotus eaters" this was the plant he was most likely to have been thinking of.
The sacred lotus of India and SE Asia is Nelumbo nucifera, which is not a waterlily at all, however its similarity to waterlilies caused it to be misidentified as one for a long time. And both can be easily mistaken for one another in artistic and figurative representations. These medallions are ceiling paintings from a temple in southern India. The one on the left could be the golden lotus (below) and the one on the right either a waterlily or a sacred lotus.
As if that wasn't enough, the golden lotus, a much revered plant itself, is actually a many bracted, many flowered infloresence in the banana family (Musella lasiocarpa). And this sort explains these cases of mistaken identity. The flowers of waterlily and the sacred lotus are both pretty large and have lots of overlapping petals. And in first appearances, the golden lotus looks likewise, although it isn't just one flower at all.
And to further add to the confusion the genus Lotus (called bird's foot lotus) belongs in the bean family, and why this bean came to share this name is unknown to me.