Wednesday, November 4, 2009
One of my earlier posts about a hike in Wissahickon Valley Park included the above photo of an unusual looking plant. I thought for sure those weird growths were some type of shelf fungus, but I did not see anything that looked like it in the fungus field guides. Thank you to Beetles in the Bush for identifying this plant for me. It is Euonymus alatus, aka Winged Euonymus for obvious reasons, aka Burning Bush because of how it looks in the Fall.
Euonymus alatus is native to Asia, and was brought to the US starting in the 1860s as an ornamental plant. Wissahickon Valley Park was established in 1868, so the timing works out. Today this is considered an invasive plant.
I have tried in vain to figure out why this plant has wings. I did find out that the wings are made of cork, a material which is part of the bark of many types of plants, but is usually underneath the outer bark layer which is called the phellum. I even found a few sources that explain in very technical terms HOW the cork manages to grow into these wings.
But what I was looking for is WHY these wings grow. What evolutionary purpose do they serve? Also, why are they in such neat rectangular shapes? Most shapes in nature seem to be curved rather than so rectilinear. Unfortunately I was not able to answer these questions. Until I do, I propose that the wings are the plant's attempt to mimic the birds they see flying above them. Many generations from now, a Euonymus alatus will grow wings big enough for it to take off. Then the invasion will really begin ...
at 11:53 PM