I posted in "Can You Prepare for the Apocolypse" that I would maintain certain things/books. I failed to mention Matt Warnock Turner's "Remarkable Plants of Texas" (my copy, Univ. of Texas Press). It is generic to my area. The author profiles plants as "uncommon accounts of our common natives". One example, the Yucca is of use in "foodstuff, fiber, soap, tanning agent, medicine, building material, and fuel." I defined permaculture to a relative as the propagation of multiply useful native periennials. The live oak, and pecan being food, shade, fuel, building material, etc. The native periennial is so obvious to our survival, that it may often be overlooked. Should I ever start a primitive skills camp or workshop, it's core cirriculum would be plant knowledge (foraging). Such a practical rebuilding of the homestead needs a chapter.