Polygonaceae
Having both acmon blue sexes in the same photograph is very helpful, because I've had some difficulty distinguishing between them on their own, since lighting and wing angle can be so variable and deceptive. Ya, I know, I've been told repeatedly, "Get a photograph of the topside (dorsal), then it's easy to tell them apart." Ha! As if it were that easy! I'm thrilled whenever I can get any photograph at all that's not a total fuzzy blob. Seriously. And, after seeing numerous butterflies in a day, I never can remember if the topside of butterfly #34 was blue or brown while it flew away. Maybe other people have an easier time of it? This is only my second photo of mating butterflies that I've managed to get all year. The first were Edith's checkerspots back in May at Pinnacles. As with the Melissa blues, the female acmon blues have a browner ground color on the underside (ventral).
I'm noting the plant they're perched on while they do their thing, but that may not mean much. While I do have other photographs of worn female acmons nectaring on seacliff buckwheat, I don't have any photographs of egg-laying on this plant. It cannot be assumed seacliff buckwheat is the larval host plant of these acmons. I didn't notice any other buckwheats or lotuses in bloom in the area, which also may not mean much. In any case, I thought this would be a good time to showcase this lovely local buckwheat...
tight pom-pom shaped multi-colored mature pink blooms
narrow arrow-shaped leaves, cobweb top and felty bottom
seacliff buckwheat from a distance
(it apparently likes "cliffs" with a marine influence)
another pair of mating acmon blues on a drier seacliff buckwheat flower head
(browner female left, male right)
ps 11/21/14 - Jim Reveal confirmed this ID, and if he recognized varieties, he'd call this var. parvifolium.