Acer pensylvanicum- bark. Photo by Katherine Wagner-Reiss.

Contributed by Katherine Wagner-Reiss

Acer pensylvanicum was one of many New World species exported by the Philadelphian plant explorer John Bartram (1699-1777) to his European colleagues, including to a patron, Lord Petre who carefully maintained many of the samples in his personal herbarium collection.

Acer pensylvanicum- leaves. Photo by Katherine Wagner-Reiss.

What does the genus name “Acer” tell us?  Acer is the Latin name for maple. Acer means sharp, referring to the fact that the Romans used the hard wood of the maple to make spears.

Bartram’s specimen of Acer pensylvanicum, in the Petre Herbarium at the Sutro Library, San Francisco State University. Notice Bartram’s handwritten note describing the maple before it had been named A. pensylvanicum.


So why is this maple named A. pensvlvanicum and why is it spelled with only one “n”?  In 1681, King Charles II granted a land charter and called the tract ‘’Pennsylvania” meaning “Penn’s Woods” to honor William Penn’s father, Admiral William Penn. Spelling not being consistent in the 18th century, however, the name appeared variously as “Pennsylvania,” “Pensylvania” (as on the Liberty Bell), and even “Pennsilvania.” No matter how you spell it though, “pensylvanicum” is the perfect choice of specific epithet for this understory tree native to the Pennsylvania (and other Northeastern) woods. This Latinized name was recorded in 1753 by Linnaeus, the Father of Taxonomy.  Once a plant is officially named, the rules allow for no change in the spelling.  So the one “n” is here to stay.  I like to think of it as a quaint reminder that, before Noah Webster published his 70,000-word dictionary in 1828, American English spelling was simply not standardized.

Common names also tell us a lot about a tree: think of moosewood (moose and deer browse on the leaves and twigs), striped maple (look for the white stripes on the bark), goosefoot maple (did you notice the leaf shape?), snakebark maple (the bark looks like snakeskin), whistlewood (small branches are easily made into whistles), and Pennsylvanianvaahtera (the Finn’s double the “n”).


Morris Arboretum is home to three Acer pensylvanicum trees, unique because they are the only snakebark maple native to North America. You can find their locations on the Collection Connection or in the Morris Arboretum Plant Catalogue.


Katherine has her Certificate in Botany from the New York Botanical Garden and is a botanical tour guide and free-lance writer.