Lathyrus graminifolius is most easily identified by the compound leaves with long filiform leaflets. The flowers are pink marked with purple, and turn orange as they age. Lathyrus graminifolius is found at upper middle to upper elevations in the Gila National Forest.
Lathyrus and Vicia are two genera that can be difficult to tell apart without using a loupe to examine the style. If one carefully removes the petals and the stamens so that just the stigma remains, the difference becomes obvious. In Lathyrus, the style is hairy up and down an entire side, whereas in Vicia there is just a tuft of hairs below the apex.