Douglas-fir

Douglas-fir trees, Pseudotsuga menziesii, always remind me of Oregon.  The name just brings to mind the massive giants of the Cascades, but the doug firs in the mountain west never seemed the same as those.  I used to think that the noticeable differences were simply due to the climate, the altitude and cold of Wyoming producing smaller, less robust specimens than the moisture of the northwest. Today, I found out otherwise:  rocky mountain douglas-fir is a separate subspecies (var. glauca) from the coast variety (var. menziesii).  There is even some debate over whether they are two distinct species.
Doug firs are a problem in other ways, too.  They are not true firs, since, though their needles are similar, their cones hang downwards instead of upwards.   That's why they get their special hyphen, to differentiate from real firs. 

Westernexplorers.us states that the local douglas-fir's variety name glauca "refers to a whitish cast over the blue-green color which is slightly different from the green needles of the Douglas fir of the west coast." (I notice that they forgot the special hyphen.)  Conifers.org explains that the bark of the rocky mountain trees is "often rough and black compared to the typically brown, often flaky bark on the coastal variety".  These are some of the distinctions that tended to hinder my identification, so I was pleased to learn of them.  Some websites described the smell of a broken branch to be citrusy, but I dislike the idea of purposely breaking the branch of a live tree to test this!

I am only ever confident of my identification of these trees when cones are present.  Douglas fir cones are unique in that they are the only cones that have pointy bracts hanging down.  Various websites described one of these bracts as resembling the rear feet and tail of a mouse hiding under the scales of the cones.  I find this someone dubious, but now I know I will see little scaredy mice whenever I see a Douglas-fir cone.