Black Knot Fungus. Our native Black Cherry trees (Prunus serotina) battle a fungus. The fungus infects the tree and causes abnormal cell growth. Those large black blobs are actually the tree’s own cell growth covered with a skin of fungal fruit! These large black cankors can be seen from some distance, but up close you’ll notice the tiny black fruiting bodies (the tiny round things). When it rains in the spring, these fruit rupture and the spores become airborn….in search of a new victim (which includes plums and apricots as well, among others). Often times the tree survives the attack, and can even endure a prolonged infection. Interestingly, upon closer inspection you may notice that the infection may cause the tree’s sap to drip from wounds or otherwise accumulate in blobs. Apparently insects and birds enjoy this little treat!
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I wonder how long the Black Knot fungus has been around? I found a couple of sources that said it is a native fungus. If it has a long evolutionary history with the wild Black Cherry, it is possible that it aided in the making of hunting tools for American Indians and their ancestors. The sap makes a fairly good glue for attaching projectile points to darts and arrows. When it dries, it is very hard but brittle. I remember experimenting with this sap when I was younger. My brother mixed some ash with the sap in an effort to improve the strength of the “glue”…can’t recall if that was an improvement or not (and elmer’s glue mixed with dirt won the day!).
Here’s a photo of some dried cherry sap I plucked from a tree (looks like amber). Next to it are a couple of broken quartz projectile points…artifacts left by people that lived in the Charlottesville area 6,000 – 8,000 years ago.
Connections are everywhere, in space and in time. And the relics of past events, human and non-human, are around us all the time. This is why a little walk in the park can be tantamount to time-travel.