Colorful description

After realizing that many colors of flowers in A Southern Garden are called by the names of pigments or at least names found on tubes of oil paint, I started wondering about names unfamiliar to me. The first two are amparo blue and smalt blue. These days color is often described using Pantone numbers. I wonder whether she was using this NBS/ISCC system. Esmalte is enamel in Spanish (is it nail-polish also?). Amparo blue seems to be a sort of Dutch blue or Wedgwood blue. In Spanish "amparo" is heard in religious contexts (protection, aid, refuge, succor, defense); is the blue to do with the color of the cloak of some manifestation of Nuestra Señora? Elizabeth Lawrence also uses "nopal red" fairly often. Is there a standard color-naming system consistently used now or at any time in the past to attempt to describe botanical or flower colors? Now, as I come to Lawrence's entry on oxblood lilies (now known by a different botanical name, but obviously the same flower), she associates them with Texas and describes their color as being "between the ox-blood and carmine of Ridgway." In the front matter of the book, she says this: "In checking colors of the flowers I have used Robert Ridgway's Color Standards and Nomenclature (Washington: The Author, 1912)." Other sources say that the book was published in Baltimore. At any rate, it was intended to be used to describe birds. On this page is an image of the book. The system is here described as "a mixture of pigment names, those used in industry and those derived from the Latin, such as the names in Charelton’s glossary. So we still have Cinnamon-buff, Vandyke-brown, Vinaceous-tawny, Violet Ultramarine, Ferruginous, Carrot Red, Lettuce Green and Cobalt Green."