[2] The genus is traditionally placed at family rank with the waterleafs (Hydrophyllaceae) in the order Boraginales.

The Angiosperm Phylogeny Group, recognizing that the traditional Boraginaceae and Hydrophyllaceae are paraphyletic with respect to each other, merges the latter into the former and considers the family basal in the Euasterids I clade.

Other botanists[3] continue to recognize the Hydrophyllaceae and Boraginales after analysing the secondary structure of the ITS1 genetic region rather than its sequence for these higher taxonomic levels.

There are reports that glandular hairs of stems, flowers and leaves of some species of Phacelia secrete oil droplets that can cause an unpleasant skin rash (contact dermatitis) in some people, specifically from P. brachyloba,[5] P. campanularia,[6] P. crenulata,[5][7] P. gina-glenneae,[8] P. grandiflora,[5] P. ixodes,[6] P. minor,[9] and P.

[9] The mining bee Andrena phaceliae is a specialist pollinator of this genus in the Eastern United States