Butterfly was nectaring on the blossoms of Alkali Heliotrope. Link to Purplish Copper butterfly observation: https://www.inaturalist.org/observations/219241441
Alkali Heliotrope (Heliotropium curassavicum) Native, perennial plant in the Borage (Boraginaceae) family that grows in many plant communities throughout California and beyond. Leaves are fleshy. Flowers are white, narrowly bell-shaped with a purple throat. Inflorescence forms a loose coil with double rows of symmetrically placed flowers. It is a favorite butterfly nectaring plant. Peak bloom time: May-August. It has many common names including: Chinese parsley, Heliotrope, Salt heliotrope, and Seaside heliotrope.
Calflora (includes species distribution map in CA) https://www.calflora.org/app/taxon?crn=4060 and sightings in Monterey County: https://www.calflora.org/entry/observ.html?track=m#srch=t&lpcli=t&taxon=Heliotropium+curassavicum&chk=t&cch=t&cnabh=t&inat=r&cc=MNT
Jepson eFlora https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=59914
Plants of Monterey County: an Illustrated Field Key, 2nd edition, Matthews and Mitchell, 2015, pp. 98-99.
Flora of Fort Ord: Monterey County, California, David Styer, 2019, p. 66.
Monterey County Wildflowers: a Field Guide, Yeager and Mitchell, 2016, p. 195.
Monterey County Wildflowers https://montereywildflowers.com/heliotropiaceae/
Baja California Plant Field Guide, Jon P. Rebman , Norman C. Roberts, 3rd. ed, 2012, p. 159.