I live in high desert New Mexico, zone 7B (temperature range 10f - 105f, hot summers, average 7" of rain annually, mostly in late summer), and just discovered this Vetch growing wild. It's very exciting to find a useful plant growing wild, and I would like to learn what variety it is so I can buy like a trillion seeds and plant it among my grain crops. Does anyone know what variety this might be?
Pretty sure it's an American Vetch, Vicia americana:
The USDA says it grows on 10 inches of rain a year, which explains why in my climate it's growing near my concrete slabs: we only get an average of 7" of rain a year, but the soil beneath the slabs stays moist for much longer than bare soil.