Ok so when I try to design with mistflowers or order them from various nurseries they often have different names so here’s my attempt to clarify for my own future reference, but maybe it will be helpful to you too. Even the botanical names were changed on some of these in recent history to the confusion is real.

Mistflowers- all are native to Texas

Conoclinium coelestinum- Blue Mistflower- has non-lobed leaves and thrives in shade. Perennial groundcover type. Blooms all summer.
Conoclinium greggii- Gregg’s Mistflower- has deeply lobed leaves and thrives in sun and part shade. Perennial groundcover. Blooms all summer.
Ageratina havanensis- White Boneset- deciduous shrub with a weeping habit. Blooms white in fall.
Chromolaena odorata- Fragrant mistflower- has blue flowers, the entire plant is similar in shape and size to blue plumbago or flame acanthus, can grow in sun or shade. I treat it as a perennial in Austin, so I cut it down to the ground each winter.
Ageratum spp- Whiteweed or annual mistflower- Usually planted as an annual bedding plant during the warm season. Blooms all summer. There are many species and cultivars. Most are short but some are taller. All are native to the new world.