Here is a link to the plant exhibit diagram that you probably saw. This one is from 1983. https://apeekatthepeak.org/scenic-drive-diagram-of-plant-sites/ Just cut and paste the link into your browser. The map is also listed in the Scenic Drive Directory. Editor

You are right. There is such a map. It was developed in the late 1960s. Unfortunately the map is obsolete. The plant signs and the small Scenic Drive park that were on Cave Creek Road are gone. The original monument sign is still there but it is fenced in. The Scottsdale Road section of the Scenic Drive was restored by our organization and Scottsdale in the late 1990s. At that time an exhibit area was created that includes drawings and information about the types of plants found it the area. The plant signs along the road were also restored but unfortunately we do not have an up-to=date map of where they are located, as the area has developed it’s convenient, safe and surrounded by desert plants. I beIieve the map you saw is in the 1968 Maricopa County report that is included in the history section of this website. I will double check and post another response. Editor