'Vesuvius' was discovered as a variant by a production manager at a company named 'Oriental Aquarium' according to Eu It Hai who also mentioned that this had been misreported in previous literature stating that Ms. Hwang discovered the aquarium plant.
The parent plant was a single specimen of Echinodorus angustifolia.
Oriental Aquarium decided to market Echinodorus 'Vesuvius' through Stoffels, their subsidiary company. Kelly Teo (Stoffels' managing director) felt it reminded him of smoke and ash spiraling out of a volcano hence the name E. 'Vesuvius'.
Paraphrased from: http://www.floridaaquatic.com/articles_echinodorus_vesuvius.html