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Great Taxonomic Gaffes
By Arthur O. Tucker

Outside of my family, my real passion is my garden. Thus, to be able to talk shop and compare notes, I belong to many horticultural societies. But because I was trained as a botanical taxonomist, I often hear plant names used in a way that sets my teeth on edge. I have learned to keep my mouth shut; no one really likes to be corrected by the self-righteous, especially about anything as esoteric as nomenclature. Yet, as Henry Higgins declared in “My Fair Lady,” your speech sets you apart. Likewise, your use of plant names distinguishes you as more than an armchair gardener.

Any level of taxonomic naming is called a taxon (taxa in the plural). Most gardeners are concerned with minor differences, as exemplified by a verticillium wilt-resistant tomato, a cold-hardy rosemary, or a grape-scented iris. Thus, they are concerned with a taxon called “cultivar.” Derived from “cultivated variety,” the term cultivar is used by botanists and horticulturists to denote anything from a very minor variation, such as the white-flowered selection of red valerian (Centranthus ruber ‘Albus’) all the way to intergeneric hybrids of orchids. The cultivar is normally enclosed within single quotes with the first letter of the name capitalized. Since January 1, 1959, cultivar names must be in a modern language, not Latin. Previously, many cultivars were described as botanical varieties or forms even though they arose in cultivation. For example, the zebra iris arose as a pre-1901 mutation or sport of Iris pallida with cream edges along the leaves and became I. pallida ‘Variegata.’ But if this variegated iris were introduced today, its Latin cultivar name would not stand up in a court of botanical nomenclature.

Because some cultivars involve extensive hybridization, it is rather pointless—and often confusing—trying to pin down a species. Thus we write Iris ‘Song of Norway’, not, I. germanica ‘Song of Norway’ since the true I. germanica contributed little to iris evolution.

Another misuse of taxonomy involves the concept of species. A species is properly the genus plus a specific epithet (specific name—abbreviated “sp.,” or “spp.” for the plural); because a species has two names, it has to be expressed as a binomial. As a species humans are Homo sapiens, not just sapiens! For the same reason you don’t want to be heard saying, “Well dentate is not hardy for me.” You would be saying your “toothed” isn’t hardy. A toothed what? The statement that “Lavandula dentate is not hardy,” however, has real meaning, since you are now referring to the toothed lavender. To further define a species, the authority who first named it is also appended in formal botanical usage. Thus, the full, correct name of the toothed lavender is L. dentate L., referring to Linnaeus’s publication of this name in 1753 in his Species Plantarum. For most horticultural use, though, the authority is omitted.

Hybrid species are designated with a multiplication sign “X” although the lower-case letter “x” may also be used. Peppermint is a hybrid of spearmint (Mentha spicata) and water mint (M. aquatica) and is written as M. xpiperita. Intergeneric hybrids, such as heucherella, a hybrid of the two genera Heuchera and Tiarella, have the “x” before the genus; thus the new genus xHeucherella. Some nursery catalogs list an “x” before certain cultivar names. I’m not sure what this really means; the International Code of Nomenclature for Cultivated Plants doesn’t allow the use of “x” before a cultivar name.

What really makes me cringe, though, is hearing someone discuss, for example, the “family of lavenders.” Family? Lavandula is a genus containing many species. It is in Lamiaceae (alternatively, Labiatae), sometimes called the mint family, but neither lavender nor Lavandula is a family. Lamiaceae includes many other plants related by their common attributes of zygomorphic (bilaterally symmetrical) flowers, square stems, glandular hairs filled with essential oils, and so forth, such as the rosemarys (the genus Rosmarinus), true mints (the genus Mentha), and sages (the genus Salvia), among others.

Understanding botanical nomenclature has very real applications beyond trying to impress your friends. Knowing the related species will indicate potential for hybridizing, grafting, medicinal properties, etc. For example, when taxol was discovered in the Pacific yew (Taxus brevifolia), chemists began searching our cultivated yews, and behold, taxol was there, too. And deer-plagued gardeners are noticing that if deer leave one plant alone, they may also bypass its near relatives.

Oh, finally, don’t be afraid to pronounce a botanical name. The “pronunciation police,” as I term some self-important critics, usually don’t know what they are talking about anyway. While it’s helpful knowing Latin to pronounce botanical names, many names aren’t really Latin after all, but are derived from Greek and other roots. I have yet to meet two botanists who pronounce Aeschynomene the same way!

Ultimately, since communication is the goal, go for the most melodious-sounding pronunciation for the audience. Most gardeners (and botanists, too) mix classical Latin and English pronunciations. If you want to cause an uproar in your discussions, try using the classical Latin pronunciation of Pinus ponderosa (the “i” in classical Latin is pronounced similar to the “i” in “machine”). Freudian compulsions do have their limits!

Arthur O. Tucker is a research professor in the Department of Agriculture and Natural Resources at Delaware State University. He was senior author for an appendix in the 1995 revision of the International Code of Nomenclature for Cultivated Plants.

MUCH ADO ABOUT TRADEMARKS

This spring as you fill out your catalog plant orders, you may notice that some of the descriptions are rife with strings of letters like ‘Migtig’, or maybe ‘Smaragd’. A few years ago, these would have been ordering codes. Today, they’re the names of the plants. How would anyone expect to sell plants—no matter how “rare and choice”—with such ugly monikers? They don’t, which is exactly the point. In recent years a number of nurserymen—none of whom have yet to challenge Donald Trump or Bill Gates as moneymakers—recognized that they could increase profits immeasurably by patenting and trademarking their products.

If a grower has a new plant—whether a naturally occurring mutation with bigger flowers or variegated leaves (a selection) or a hybrid developed through years of painstaking crosses—he or she can register it as a cultivar through an International Registration Authority. Cultivar names have no legal standing, but are “gentlemen’s agreements” intended primarily to help gardeners know exactly what they are buying and growing. The person who registers the cultivar has no ownership of the plant name or its germplasm—the seeds or cuttings that allow it to be reproduced. They will profit only from whatever propagating, distributing, and selling they actually do.
If a new introduction is patented, the patent owner can control the propagation, distribution, and sale of the clone through royalty agreements—anyone else who sells the plant has to give them a cut—but only for 17 years.

A trademark does not control distribution and sale of a particular product, but it does control the use of a name—indefinitely, as long as it continues to be clearly linked to one origin in the public mind. (Aspirin was originally a trademark symbolizing one originator of acetylsalicylic acid, but lost its protection after being applied in general use to all similar products.) Thus anyone can sell as many trademarked October Glory maples as they like, as long as they sell them by the cultivar name ‘PNJ0268’ and not the appealing trademark name marketed as representing a superior plant.

It’s pretty clear that when trademark laws were passed, no one thought they would ever be applied to plants. When a trademark is applied for, the product must have a separate generic (common) name as well: hence the conception of a generic name that can double as a cultivar name in the scientific community, while having absolutely no appeal in the marketplace. (A trademark can be formally registered, or become official through common use. Thus the name under which a patented plant is sold is likely to be accepted as a trademark when the patent expires.)