On a hike on Signal Mountain here in southeast Tennessee Sunday I found a couple of trees that confused me. It looks like a deciduous conifer. I'm told it may be a Black Birch, but not sure about this. If so, what is the difference between cones and catkins?
Sweet Birch Betula lenta. The difference between cones and catkins is in formation and internal structure; superficially, they can look very similar, as you've found here. A nice example of convergent evolution, with the same purpose (seed dispersal) performed by structures of similar appearance, though different origin. Cones are produced by gymnosperms, with the ovules exposed (gymnosperm = 'naked seed') at pollination; catkins are produced by some angiosperms (flowering plants), with the ovules enclosed in a flower ovary. Yours here are catkins, not cones, as birches are angiosperms.
Thanks Michael, are these trees indigenous to this part of the U.S., or would they likely have been brought to this area? I haven't seen very many of them here, but I will keep my eyes open for them from now on.
Not really flaky no, I'll try to go back and get a close-up of the bark of the two I saw, this one is more of a silouette..., not sure it will aid any at all.
Hi Mistwalker, Yes, native in eastern TN. Hi Tipularia, Not from the key I followed; River Birch has 5-9 pairs of leaf veins, whereas Sweet Birch has 9-12 pairs of veins; Mistwalker's plant shows 12 pairs of veins (leaf in the last pic).
