Aspen and poplar - what's in a name?

What's in a name? Plants are named by way of binomial nomenclature - a first and last name - expressed as Genus species or Genus species. If John Smith were a plant, for example, its name would be Smith john, either in italics or underlined to give the reader a heads-up on its taxonomic status.

This binomial nomenclature can be referred to as a scientific, technical, or Latin name but I recently came across the term botanical name which makes the most sense for me. Scientific or technical seem daunting to the lay person, and Latin may or may not be accurate since it may be a variation of a Latin word, a Greek word, or something Latinized from Greek. So, botanical name is the term for me since it's a botanical specimen that I'll be discussing. Binomial nomenclature is used for animals, too, so I'll have to think about that.

Plants may also go by a number of common names, some of which they might share with another plant or two. Trees in the Populus genus go by poplar and aspen, for example. While multiple or shared common names can lead to some confusion when attempting to discuss a tree, the botanical name gets you directly to the species of interest. The Forest Trees of Maine describes three Populus species: P. tremuloides, P. grandidentata, and P. balsamifera. You may find others that have been planted in parks or urban developed areas but if you learn these three, you'll be well on your way to recognizing other trees in this genus and distinguishing them from the Maine forest tree species.

P. tremuloides and P. grandidentata go by the common name aspen and have some similarities that distinguish them from P. balsamifera which goes by the common name poplar. See the chart below for some key characteristics. This photo shows P. tremuloides (upper left), P. balsamifera (upper right), and P. grandidentata (bottom). The darker leaves are the upper side, and the lighter leaf shows the underside.

Trembling aspen (P. tremuloides) gets its name from its leaves that tremble, or shake, in the wind thanks to its flattened petioles. Big-toothed aspen (P. grandidentata) also shakes in the wind, but gets its common name from its leaves' large, coarsely toothed margin. Balsam poplar (P. balsamifera) is also known as Balm-of-Gilead but balsam poplar is also used interchangeably with cottonwood (P. deltoides) - the balm is made from the sticky buds.

	P. tremuloides	P. grandidentata	P. balsamifera
Petiole, in cross-section	Flattened	Flattened	Round
Distribution	Statewide	Statewide
Shade tolerance	Intolerant	Somewhat tolerant
Mature bark	Smooth top, ridged below	Smooth top, ridged below	Smooth top, ridged below
Alternate leaves	Round, short-pointed, finely toothed	Broadly egg-shaped, coarsely toothed	Ovate, fine round teeth, rusty blotches below
Buds	Dark brown, shiny, sticky	Dull gray, slightly hairy, not sticky	Resinous, sticky
Flowers	Catkins before leaves	Catkins before leaves	Catkins before leaves
Wood (see linked article for more info)	Close-grained, soft, little scent	Close-grained, soft, little scent	Coarser-grained, foul odor when green