Citron
There are also a number of citron hybrids; for example, ponderosa lemon, the lumia and rhobs el Arsa are known citron hybrids, some are claiming that even the Florentine citron is not pure citron, but a citron hybrid.
Chrysopogon zizanioides
Vetiver is most closely related to "Sorghum" but shares many morphological characteristics with other fragrant grasses, such as lemongrass ("Cymbopogon citratus"), citronella ("Cymbopogon nardus", "C. winterianus"), and palmarosa ("Cymbopogon martinii").