Agave univittata

syn Agave lophantha

These are often seen as separately named plants but are treated as being  synonymous by Gentry.  I have raised seedlings of both that are to my eyes identical - extremely similar to those named as lechuguilla as well, incidently - and they are all have straight dark green leaves with a central pale band and marked with even darker longitudinal dashes, wavy margins to one extent or another and a horny, woody margin from which the teeth arise.  Very attractive plants, whatever they are called, and should be quite hardy. ( 1999 )