"One of the liveliest and most predictable subjects
of gardeners' conversation is the problem of changes in plant names, instituted
for mysterious reasons by interfering botanists."
Brent Elliott, librarian for the Royal Horticultural
Society, wrote those words in an article for the March 1994 issue of the
journal The New Plantsman. The
article described the 150-year journey the Douglas fir took on its way to
becoming Pseudotsuga menziesii. It
was an arduous trip, and full of changes--21 of them, in fact.
Gardeners shake their heads in disbelief
at the fact that
the botanical name for the Douglas fir was changed 21 times, and had a total of
19 different names. Why would it
take so long to reach a "correct" name? Why would it be so difficult? Why would a plant name need to be changed at all--and
sometimes more than once? Those
questions are relevant not only to historical nomenclature events, but also to
the changes that are occurring today.
Botanical names get changed for one or more of several
reasons. The reasons include the
fact that the first name assigned was done so with insufficient knowledge of
the plant's characteristics. This
shows the Linnaean classification method:
plant names were assigned according to physical structure, especially
During Captain Vancouver's 1791-1795 voyage, Archibald
Menzies gathered the first sample of the Douglas fir for European
botanists. The tree was named
Pinus taxifolia, in part because just about any conifer at that time was
considered a Pinus, and also because the cone from the sample had been
lost. Here is a perfect example of
lack of information leading to the wrong name.
The Douglas fir's story includes at least one other
reason plant names change: the
rule of priority. Sometimes a
plant's botanical name changes back to an earlier name, which is deemed correct
Obviously, the name of a species
of rose is not going to
be changed to Daphne just because someone mistakenly called it that in a
published article, no matter when the article appeared. But if a legitimate name was
prior to a current name, then the switch takes place. The genus name for the Douglas fir--Pseudotsuga--that was
published in 1867 won that race.
You'd think that once all the rules have been followed
and a name is applied, that would be the end of it. But there are and probably always will be ongoing
discussions within the taxonomic world over whether a species should retain
this name or reject that name.
Looking at just a few titles of articles printed in Taxon, the journal
of the International Association of Plant Taxonomy, shows us this.
to conserve the name Adenophyllum
(Asteraceae)" by Kanchi M. Gandhi appeared in the May 2006 issue, while in
the same issue "Proposal to reject the name Ipomoea glaucifolia
(Convolvulaceae)" by George W. Staples was printed. I'm not sure that we could say
controversy rages over the subject of plant name changes--we're such a polite
bunch--but it does appear to be a never-ending topic of debate.
You can probably think of some
changes on your own. Hosta used to be Funkia, some
Gaultheria species used to be Pernettya, and Hebe used to be Veronica. Hang on, come
to find out Hebe has been
put back into Veronica. It's not a
far-fetched decision: we can see the similarities between the spikes of tiny
flowers in perennial veronicas and shrubby hebes, but still, it's slightly
jarring to try and get used to.
It's possible that moving Hebe into Veronica has
something to do with the way taxonomists--those who classify plants--work. There are
generally two camps of
taxonomists: lumpers and
splitters. Taxonomists who are
lumpers see many plants in one group, while splitters like to dissect,
splitting a genus into several genera.
The lumpers appeared to have won the battle of Hebe/Veronica.
Mahonia is another battleground. Splitters contend that Mahonia
(compound leaves!) and Berberis (leaves in three! thorns!) belong to separate genera, but lumpers have long
held the belief that all Mahonia species should be in Berberis. You will find it both
on which catalog or book you read.
Occasionally the discussion of where a plant belongs,
taxonomically speaking, takes a surprising turn. Most gardeners are familiar with the Leyland cypress (x
Cupressocyparis leylandii), an intergeneric hybrid of garden origin.
The parents of the Leyland
cypress are the Alaskan cedar
(Chamaecyparis nootkatensis) and the Monterey cypress (Cupressus
macrocarpa). Among taxonomists,
there were always rumblings about this: many were not convinced that the
parents were assigned the correct classification.
Then, in 1999, an entirely new plant was found
Vietnam. It's a conifer, and was
given the name Xanthocyparis vietnamensis. Taxonomists realized the Alaskan cedar should be in the new
genus, and moved it there.
Xanthocyparis nootkatensis it is!
Except that in 2004, another botanist pointed out an
earlier published, legitimate name for the genus. Here is the rule of priority again. He proposes that the genus be
Callitropsis nootkatensis, a name published in 1865.
And so it goes.
long it takes for changes to filter down to the level
of plant tags at nurseries is difficult to say. When Actaea absorbed all the Cimicifuga species, it seemed a
fairly short time before we saw the new names at the nursery. Smilacina was taken
into Maianthemum in
1986. I had no idea that the
starry false Solomon's seal in my garden is no longer Smilacina stellata, but
Look for more changes, especially with the ability to
compare DNA samples from different plants. The American asters are under fire, and strawberries
(Fragaria) may move to Potentilla.
Be assured that any changes in plant names have been discussed
thoroughly by taxonomists.
Although that doesn't mean they can't change their minds. Again.
you want to know more?
All the rules for assigning plant names are in The International Code of
Botanical Nomenclature (ICBN). You can find a copy at the Elisabeth C. Miller Library, but I must tell you it's dry reading--rules, rules and
more rules. Information online at: www.bgbm.fu-berlin.de/iapt/nomenclature/code/SaintLouis/0000St.Luistitle.htm
I keep up with the gardener's version of botanical news by reading the Royal Horticultural Society's
journal The Garden. To check on correct names, I pick up The Plant Locator: Western
Region by Susan Hill and Susan Narizny (Timber Press, 2004, $19.95) or go online to the RHS Plant Finder site: www.rhs.org.uk
and the reverse synonym finder page at: www.rhs.org.uk/rhsplantfinder/reversesynonyms.asp