Before we get started this week, a couple of announcements:
Michael’s classes start next week! “What Plant Is That” starts on Monday, and “Garden Design” begins Thursday. Both are 6 weeks long. See the web site for more: www.msadesign.com.
When you have the time, do notice plantings on the south side of Pine Ridge Road, at Kensington; and have a look at plantings around the I-75 interchange at Pine Ridge Road. I’ll cover both of these in a few weeks.
Let’s make it hard
Now: lots of people wonder why we bother with the scientific names of plants. Why say Trachelospermum asiaticum when Asian Jasmine is so much easier to remember and pronounce? Some of the “old-time” gardeners — the folks who have the most knowledge about plants — ask this question with a revealing smile, intimating that scientific names are college-boy silliness.
Is this true?
No. It’s just that they are delightfully polysyllabic, consistent with your Design Professional’s merry philosophy of eschewing austerity in favor of abstruse recheré.
And there is this: The pointy-headed people are actually on to something here. Scientific names, and the way they are written, are precise. The International Association for Plant Taxonomy polices the effort, accepting names only when following particular rules, and when published by reputable sources.
For all of its precision, the system is actually quite straightforward. And, do remember this important fact: plants are forever evolving. Categorization is based on how closely they are related to a common ancestor. This means that the names not only identify individuals, but also place the individual in the march of evolution.
Let’s look at how the system works.
The binomial system
Remember high school biology? All creatures are described by a system of increasing specificity, starting with Kingdom, moving through division, class, order, family, and then genus and species. This last-species-is a population of creatures able to reproduce with fertile offspring (no mules need apply). We owe a debt to Carolus Linnaeus, the Swede who invented this ‘binomial system’ in 1753.
It’s the last two categories that have attracted our interest this week because they are the workhorses of plant names. Two words, though, may not be sufficient to describe a plant. To that end, there are several accepted ways to delineate the subject.
Scientists are rightfully jealous of their discoveries. In the botanical world, we recognize the naming scientist by adding the name directly to the right of the species. When you see, for example, Myrica cerifera L., you know that this plant was named by Linnaeus. Over the course of time, though, many species have been named by virtue of a more cursory investigation.
In the case of plant material, especially, additional subdivisions are quite useful:
Sub-species are usually geographically separated populations that may or may not become species, but do have different characteristics. When describing them, use the abbreviation “subsp.”. Most crop plants fall into this category, and so do cat and dog breeds.
A cultivar or variety show some kind of distinct variation within a population and are essentially the same thing. Do note, though, that these terms have legal definitions protecting certain rights. Write these varietal names with an italic v. followed by the the name: Genus species L. v. Variety.
And finally, there is Form. These individuals show only minor, but persistent, differences, and are sometimes related to environmental factors. They are written as f. Horizontalis, maintaining the italics, and always precede the naming scientist: Genus, species, forma alba, Scientist Name.
Beyond the species
And just when you think you’ve settled on talking about exactly the same plant: surprise! The name is changed! Ordinary wax myrtle is a native plant recently renamed by the aforementioned pointy-headed folk from Myrica cerifera to Morella cerifera. Why?
Many plants have been named based on incomplete studies or apocryphal field observations. Plant material is located on the tree of life based on the characteristics of sexual parts, the study of which is tedious and time consuming although a source of endless joy to a certain personality type. There are about a bazillion plant species on Earth, and only a dozen or so research botanists, so you can see that there is a bit of a backlog. As each plant is properly studied and described a more exact placement can be made. In the last dozen years or so we’ve seen queen palm, for example, move from Cocos plumosa to Arecastrum romanoffizanum. This is science moving forward for the good of humanity.
Michael Spencer, ASLA, has been practicing landscape architecture for 27 years and is president of MSA Design, Inc. Web site: www.msadesign.com