Goldthread (Coptis trifolia ) LC
Goldthread is a perennial herb growing from slender bright yellow to orange rhizomes. Goldthread grows in wet coniferous and mixed forests, bogs, willow scrub and tundra, in areas include Japan, China, Korea, Eastern Siberia and North America .
Goldthread, like all photoberberin dyes, is used as a direct dye, in a hot dye-bath, to obtain a bright golden yellow on silk or wool. The Micmac of the Gaspe peninsula and Acadia boiled the rhizomes to dye yellow . The French settlers in Canada adopted this dye for their woolen cloth . Japanese used Coptis japonica as a traditional dye.
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Analytical instrumentation and procedures
 Cardon, Dominique. "Natural dyes, sources, Traditions, Technology and Science" 331 (2007).
 Whitehead, R. H. (1982) Micmac Quillwork; Micmac Indian Techniques of Porcupine Quill Decration, 1600-1950. Halifax: Nava Scotia Museum. p. 68;
 Yamazaki K. The illustrated book of dye plants, vol. 1 (1985/2002). pp. 46-7.