Monday, November 17, 2014

Marescence



To keep Alzheimer’s at bay, learn a new word every day. Or perhaps one every month. This month’s word is marescence. It stems from the Latin for marescere, to wither or to shrivel. The subject presents itself every fall, but the energy to dig up the facts is not present every autumn. This time I went on a search to discover why it is that virtually all deciduous trees loose their leaves more or less on schedule—thus, hereabouts in the Midwest, they are mostly down by today. But some hang on for dear life. And some keep them until well into the coming spring. Such species, among them Oaks, Witch-hazel, Hornbeam (musclewood), Hophornbeam (ironwood), some species of Willow, and American Beech display marescence, meaning that their leaves turn color but remain attached to the branches until new budding pushes them off. The evolutionary value of this tactic is debated but not resolved.

To get this list I had to find a helpful post (link) at Penn State’s College of Agricultural Sciences. Endless blogs and chat rooms go on and on about leaves, but all are incomplete and rarely roam farther than the nearest oak.

Well, in the center of our large back yard rises a rather young American Beech. It still has all its leaves although, at the tip, they are beginning to turn brown. Finding the name of a tree merely by looking at its leaves is very time-consuming. You have to be retired to do it. One step leads to another. The images you see displayed above are the leaves of some of these species, in the order listed above. They suggest that my Fall raking will have its Spring complement as well. My images are courtesy of Wikipedia commons.

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