27 November 2024
November is a good time of year to look for hackberry trees in Pittsburgh and examine their fallen fruit. By now the pulp has worn off the pits, but unlike wooden cherry pits hackberries’ are like white seashells with a microscopic lattice of opal inside.
Learn about these amazing structures in this vintage article.
Then go find a hackberry tree (and an electron microscope).
Hackberry bark and bare branches make it easy to identify the tree, even in winter. The bark has ridges and the ridges have growth lines.
Up in the bare branches, hackberry trees often have twig formations called witches brooms, “produced by the effects of an eriophyid mite (Aceria celtis) and/or an associated powdery mildew producing fungus (Sphaerotheca phytoptophila)” — from bugwood.
Finding an electron microscope to view the opal is a much harder task.