Peppers & Confusions

I know I'm no Edward Weston, but take a look at these peppers:

But what kind of peppers are they? There seems to to be quite some confusion about peppers. I live in southern California (and come from a climate where even bell peppers need green houses to grow), but when I go to one of my local stores I often find myself being asked by the people who work there to identify the peppers I'm buying. Are these jalapeños? Could these perhaps be serranos?

Adding to the confusion is the mix-and-match of pepper names. Take the ones above for instance: Here (all local stores in my area) these peppers are referred to as pasillas, but as far as I can read on the internet the rest of the world (i.e. outside of California) agrees that these are called poblanos. To make matters worse dried poblano is known as ancho, while pasilla is commonly used about Oaxacan pasilla as well as chilaca (chile negro)...

Anyway, they're my new favorite pepper: a little hotter than bell peppers and I love the flavor. Leave them for a couple of days and they turn first wrinkled, later red.