Tuesday, May 19, 2015

Keys - Samaras - Samares

Less than three weeks ago, I started posting about the maple trees in bloom. Well, they've wasted no time! I've been watching the samaras (samara: winged fruit) developing since about May 4.

Acer saccharinum samaras
Acer platanoides samaras
Acer negundo samaras
Samaras are a useful adaptation. Because of the thin, papery 'sail' portion, this seed will travel further from the tree than other types of nuts, allowing better dispersal of seeds and therefore a better territorial expansion for the population. Note that all maple keys are samaras, but not all samaras are maple keys; many other genera of trees produce samara, including the elms and ashes.

The photo below shows a close look on an A. saccharinum samara which was not successfully fertilized and so is not developing (note the small, shrivelled samara on the right-hand side). The tree does not invest energy in developing samaras which are not fertilized, as it would be wasted energy; an unfertilized samara that flies away from the tree won't result in a new tree, so there's no point in investing the energy.

A. saccharnum samaras
In some cases the samaras are developing before the leaves. This tree looks very green and filled out, but all of that green is from samaras, not leaves. Depending on the species, these samaras will take to the air throughout the spring and summer.

Acer saccharinum crown

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