Cut a branch and press in an old coffee table book or cook book ( you can buy them at good will) or just use a big sketchbook. Press is with something heavy when you get home to keep it flat as it dries. Run air over it ( I have even put the whole sketchbook on top of the food dehydrator before). Upload an observation to inaturalist. That observation will give you the county, gps, elevation, etc. 

Then make a label on acid-fre archival paper that has the following information : 

(Next Line) Taxon name, Family

(Next Line)Blank County, Blank State. Blank location on ROAD X,  Blank Miles West of the TOwn of X,

(Next Line) Description of Habitat, ie (desert scrub/open prairie, shade woodland, etc), Description of other plants present in this plant community

(Next Line) Inaturalist Observation Number (the numbers after the slash on the web address for the Inat Observation)

(Next Line) GPS Coordinates

(Next Line) Elevation

(Next Line) Date Collected :

(Next Line) Collected by :