One would scarcely fail to recognize the Cottonwood, once its winter characters were firmly fixed in mind. The leaf scars are prominent and these, likewise, possess prominent vascular bundle scars while the buds themselves are possessed of several scales overlapping each other - having a decided "gummy" character. These characters differ considerably from those of another group of trees in the same family - the willows. Here one finds the bud possessed of but one scale instead of several - a most important character - while the leaf scar is narrow. Only one other common tree has buds protected by one scale. That is the Sycamore, familiar in many parts of the country either native or naturalized. But the winter characters of the Sycamore differ considerably from those of the Willow particularly in the case of the stipule scars which, in the latter case, encircle the twig. The walnut group would be readily recognized even without its most conspicuous character - the chambered pith. The stout twigs, large shield-shaped leaf scars and other characters proclaim it for what it is but it is the pith that is the most interesting. With your pocket knife split a walnut twig lengthwise. The pith, instead of being solid, is composed of numerous sections or chambers.
The long, slender, light brown buds which are oblique over the leaf scars and the slender, zig-zag twigs identify the beech. It is in the alder though that we find another striking character. As the willow has one bud scale; as the Sycamore has a stipule scar encircling the twig; as the walnut has chambered pith -- so the alder has buds that are stalked and the scales, instead of over lapping, are valvate - that is meeting at the edges.
Now all the tree groups mentioned had leaves that are arranged alternate on the twig consequently the leaf scars were alternate. Many trees and shrubs have leaf scars that are not alternate being opposite (as in the Dogwood and Maple) or whorled as in the case of the catalpa. This tree has large leaf scars in whorls of three along the twigs. The scars vary in size - one being larger or smaller than the other two in the whorl - and are possessed of numerous vascular bundle scars.
So study your trees and shrubs this winter. And when you come to the park for a winter outing take a few moments to examine this region botanically also. In either case you will find your time well spent and your knowledge of natural history enriched by a bit of understanding in winter botany.
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