United Kingdom
19 August 1958.
Durango, Mexico
Locality: Near the Chihuahua border, 45 miles from Parral between Ojito and Rio Balleza, after passing the highest point of the road in that region.
Coordinates: 26.2833, -106.0000
(Map it)
Elevation: 2250m.
Environment description: Damp slope by the roadside, in sun and partial shade.