Hopi black dye sunflower
Helianthus annuus macrocarpus
(Helianthus annuus also called Tceqa' Qu' Si by the Hopi)
 
I have not experimented much with Hopi black dye sunflower seeds, so the following information was taken from online sources – credits follow narrative. I have, however, found the seeds to give strong purples to black in bundle dyes and give nice color in solar dye baths, and so far have proven to not be fugitive. They are fun make eco-print designs with! My Hopi Black Dye Sunflower seeds are not intended for planting.
Package contains 28g.
 
Hopi black dye sunflowers were tended and used by the Hopi people in the Northeast part of what is now considered Arizona. The flowers were adapted to an arid climate and watered using flooded terraces, or planted in washes. The dye was used mainly on fibers for basket making but after sheep were introduced, the dye was also used on wool. Hopi black sunflower seeds were collected by Native Seed Search in 1978 from the Shungopavi village on the Hopi Reservation for preservation in their heritage seed bank, and further distribution. 
~ www.annacarolynmeier.com
 
Though lots of sunflowers seeds will give a dye - this variety gives deeper colors, gorgeous luminous purples, greys and blacks. The purple colors come from the compound anthocyanin - which I find to be a very tender thing. It is sensitive to pH and doesn't seem to respond well to heat.
~ www.snapdragonlife.com