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Knowing how plants are named is a critical skill for all arborists.
As Michael Dirr (1998) notes in his useful notes on nomenclature in the
Manual of Woody Landscape Plants, “A name is a handle by which we get to
know certain people, places, and plants.” Plant names and the many nuances
incorporated in those names help us get to know plants better.
The multiple common names of plants are often confusing. Toss in botanical
Latin, and many arborists plea to be spared the details. It brings to mind
the old student lament:
Latin is a language,
as dead as dead can be.
First it killed the Romans:
Now it’s killing me.
Confusion about names, however, is the very reason it is important to have
a basic understanding of the naming systems for plants. As arborists we
want to avoid errors, to communicate properly to each other, to grow in
our plant knowledge, and to enjoy the wonderful world of plants. When someone
asks if a red maple is a good choice for a sunny, wet site, what would
we tell them? Are all ornamental pears equally susceptible to storm damage?
What is the size of the species Viburnum opulus compared to the
cultivar Viburnum opulus ‘Compactum’, compared to the cultivar Viburnum
opulus ‘Nanum.’ Is it possible for chokeberries to get fireblight?
These questions can be answered with a good working understanding of how
plants are named and classified.
Basics of Plant Classification
Plants, like all other organisms on Earth, are classified in a hierarchical
system, starting with the species and going all the way up to one of the
kingdoms of life. This system moves from related species in a genus to
related genera (“genera” is the plural of “genus”) in a family, on through
order, class, subphylum, phylum, and kingdom. For practical horticulture,
the most important of these classification units are the species, genus,
and family. Thus, Pyrus calleryana is the Latin name for the species
known as Callery pear. Pyrus calleryana and Pyrus communis
are different species in the genus Pyrus; and Pyrus (pears),
Malus (apples and crabapples), Aronia (chokeberries), and
Rosa (roses) are some of the genera in the rose family (Rosaceae).
The most fundamental of these classification categories is the species.
The idea of a species is sometimes hard to describe, often vaguely defined
as “the basic unit of classification” or “plants of one kind.” One of the
most useful concepts of a species, however, relates to the fact that a
species is a reproductively isolated population of organisms. This, too,
is imperfect, of course, and respectable species such as red maples and
silver maples fail to read our books and cross-fertilize anyway. Nevertheless,
even though we may not always be able to precisely define species, we usually
know one when we see it. Thus, human beings, gypsy moths, the fungus that
causes apple scab disease, the dawn redwood, and the coast redwood are
all seen as distinctly different species.
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International Society of Arboriculture
