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It’s a Real Chameleon
The adage “leaflets three, let it be” is a good start in identification. Except in rare, five-leaflet populations in Massachusetts and Texas, poison ivy’s leaflets are arranged in threes. But the plant can otherwise be so morphologically variable that it confounds all but expert observers.
“Its plasticity is really crazy,” Ms. Pell said. And that has led to distinctive-looking phenotypes in different regions being designated as local species.
She begs to differ. As part of her long collaboration with John D. Mitchell, honorary curator at New York Botanical Garden, Ms. Pell has been sorting it out. …