The following is in the section entitled Cascadia Blue, Euphilotes "on Eriogonum heracleoides" (undescribed) in Pyle(1):

Page 239:
Cascadia Blue, a member of the Euphilotes battoides complex, has been recognized as distinct and will soon be elevated to species status.

The following is in the section entitled "Cascadia Blue", Euphilotes on Eriogonum heracleoides (undescribed) in James and Nunnallee(2):

Page 200:
Euphilotes on Eriogonum heracleoides was previously considered conspecific with E. battoides (Square-spotted Blue); however Warren(3), following an exhaustive study of the Euphilotes spp. of Oregon, substantially revised this group. He concluded that true E. battoides, whose type locality is in CA, does not occur in OR or WA. Until this species is formally described, we propose the name "Cascadia Blue" for Euphilotes on Eriogonum heracleoides because its range appears to encompass much of Cascadia (N OR, WA, N ID, W MT, S BC).

James and Nunnallee describe further in some detail including flight times of this common single brood species (late March - mid July) and how it appears to prolong its flight season by switching between Eriogonum heracleoides and E. douglasii.

here
or Polyommatinae here

as I read all of that. Very complicated! Unfortunately we didn't try to ID the Eriogonum, though Karen may know which one grows up there. We'll send her an email. Thanks.

Provided as an update to earlier post.

Species profiles on Euphilotes battoides - Cascadia Blue and E. columbiae.

Even at full resolution, I do not see any scintillae,
which may rule out Acmon and Lupine and a number of other "Blues".

We are specifically looking at Mt. Emily/La Grande area, about mid-way north-south in Union County in late June.

I see the specimens are adults and not cats, but that plant
looks like a species of buckwheat, Eriogonum sp.. So I suspect these are Euphilotes sp..
(I hope that is correct or else the remainder here is BS.)

Many of the Euphilotes species (aka Buckwheat or Dotted Blues) are (visually) indistinguishable
unless an association is made with a particular buckwheat species.

The plant in the specimen photo looks a lot like Eriogonum heracleoides.
A wider shot showing more of the plant would help an amateur like me, but someone can ID it from that photo.
Possible description here.

There are two main species groups of "Buckwheat"/"Dotted" Blues in this specific area.

Euphilotes battoides complex and
Euphilotes enoptes complex.

After looking at detailed maps, listed below are what I suspect are the two possible IDs for the specimen(s).

1. A species of the Euphilotes battoides complex - Cascadia Blue,
associated with buckwheat plant(s): Eriogonum heracleoides, occasionally E. douglasii.

2. Euphilotes columbiae - Columbia Dotted Blue, (former ssp. of E. enoptes)
associated with buckwheat plant(s) Eriogonum compositum, E. elatum, E. strictum.

Reference(1).

Edit:
The following is in the section entitled Cascadia Blue, Euphilotes "on Eriogonum heracleoides" (undescribed) in Pyle(1):

Page 239:
Cascadia Blue, a member of the Euphilotes battoides complex, has been recognized as distinct and will soon be elevated to species status.

Moved from Blues, Coppers, Hairstreaks, Harvesters.

Moved from Butterflies and Skippers.