![Are you an alder or a birch? Are you an alder or a birch?](https://m5.paperblog.com/i/87/874318/are-you-an-alder-or-a-birch-L-731fkV.jpeg)
![Are you an alder or a birch? Are you an alder or a birch?](https://m5.paperblog.com/i/87/874318/are-you-an-alder-or-a-birch-L-poUrMa.jpeg)
Both alders and birches are said to have smooth bark, but this is a little misleading. I think the authorities mean they don’t have furrowed bark. Many species of alder and birch have prominent lenticels -- prominent enough that the bark isn’t all that smooth.
![Are you an alder or a birch? Are you an alder or a birch?](https://m5.paperblog.com/i/87/874318/are-you-an-alder-or-a-birch-L-ahr24a.jpeg)
Lenticels are pores allowing gas exchange through bark. This is Tree #2.
Alders and birches both have separate male and female catkins (flower clusters), with the two sexes on the same tree (monoecious). Fortunately their female catkins differ, and therein lies a way to tell the cousins apart.Tree #1 was dominated by male catkins ... the guys were in full bloom!
![Are you an alder or a birch? Are you an alder or a birch?](https://m5.paperblog.com/i/87/874318/are-you-an-alder-or-a-birch-L-u0oYne.jpeg)
![Are you an alder or a birch? Are you an alder or a birch?](https://m5.paperblog.com/i/87/874318/are-you-an-alder-or-a-birch-L-GSPei4.jpeg)
![Are you an alder or a birch? Are you an alder or a birch?](https://m5.paperblog.com/i/87/874318/are-you-an-alder-or-a-birch-L-_f95nN.jpeg)
Darker woody "cones" are last year's female catkins.
Tree #2 had lots of catkins as well. The male ones were immature -- still hadn’t opened.![Are you an alder or a birch? Are you an alder or a birch?](https://m5.paperblog.com/i/87/874318/are-you-an-alder-or-a-birch-L-t73Sip.jpeg)
Young male catkins, roughly an inch long.
High on the tree were scattered female catkins from last year. Their papery bracts gave them away. These are birch cones. They’ll soon fall apart and be gone.![Are you an alder or a birch? Are you an alder or a birch?](https://m5.paperblog.com/i/87/874318/are-you-an-alder-or-a-birch-L-gCjcvG.jpeg)
Tree #2 is a birch, with pendulous papery-bracted female "cones" (click on image to view).
In the field I used my Rocky Mountain Tree Finder to key out the two trees. They are the mountain or thin-leaved alder (Alnus incana var. tenuifolia), and the water birch (Betula occidentalis). Both are fairly common along streams in Wyoming.![Are you an alder or a birch? Are you an alder or a birch?](https://m5.paperblog.com/i/87/874318/are-you-an-alder-or-a-birch-L-mmkdV5.jpeg)
Mountain alder (Tree #1); courtesy Zelimir Borzan, University Zagreb, Bugwood.org
![Are you an alder or a birch? Are you an alder or a birch?](https://m5.paperblog.com/i/87/874318/are-you-an-alder-or-a-birch-L-16ytg6.jpeg)
Mountain alder is sometimes called speckled alder, I suspect for the prominent lenticels.
![Are you an alder or a birch? Are you an alder or a birch?](https://m5.paperblog.com/i/87/874318/are-you-an-alder-or-a-birch-L-x4U9wR.jpeg)
Water birch (Tree #2) in its prime, with mature female catkins. UFEI, Cal Poly San Luis Obispo
![Are you an alder or a birch? Are you an alder or a birch?](https://m5.paperblog.com/i/87/874318/are-you-an-alder-or-a-birch-L-O3sRJq.jpeg)
The bark of water birch sometimes is a pretty red, contrasting nicely with the lenticels.
At the base of the water birch we found an old leaf. It helped with identification.![Are you an alder or a birch? Are you an alder or a birch?](https://m5.paperblog.com/i/87/874318/are-you-an-alder-or-a-birch-L-8a5o46.jpeg)
These trees became the first observations in the newly-launched iNaturalist project Plants of the Southern Laramie Mountains.