botanical Latin (notes for workshop talk)

Many gardeners are intimidated by botanical Latin and wonder why anyone would want to use scientific rather than common names for plants. But we humans tend to be able to recognize only what we can verbalize.  Among other limitations, there simply are not enough common names to go around; as you expand your knowledge of horticulture or of field identification, you will need words to distinguish the many plants you encounter. 

Common names refer only to a small fraction of plants that you’re likely to encounter on a walk in the woods or through a large garden center.  One name most often refers to a large number of related but distinct species. In addition, there are some names that have been given to unrelated and completely dissimilar plants.  For instance, “Blue Bells” has been attached to plants in at least six different families.

Two different species of Clematis, C. vitalba and C. virginiana, both with white flowers but otherwise distinct, share three or four different common names.

The name Kaffir Lily refers to two entirely different plants, Clivia miniata in the Lily family and Hesperantha coccinea (formerly Schizostylis coccinea) in the Iris family.  (In addition, the word “kaffir” has an extensive history of use as a racial slur by whites in South Africa in particular).

Some common names refer to very different plants in different regions.

Common names are often confusing or misleading. Very frequently, plants are named after completely unrelated plants.

Winter Heliotrope (Petasites fragrans) is not Heliotrope (Heliotropium), and not related to it.  Russian Sage (Perovskia atriplicifolia) is not a sage (Salvia), nor is Jerusalem Sage (Phlomis).  Wild Lilac (Ceanothus) is not related to Lilac (Syringa) and looks very different from it.  Cape Gooseberry (several similar species of Physalis, the Tomatillo or Husk Tomato, as well as the ornamental “Chinese Lanterns”) is not related to and does not resemble gooseberry (which is in the genus Ribes, with the currants) but is instead closely related to tomato.   Lavender Cotton (Santolina, in the sunflower family) is not related to, nor does it resemble, either Lavender (mint family) or Cotton (hibiscus family).

The Lily family genus Phormium is called New Zealand Flax because its fibers were used in textiles by the indigenous people of New Zealand. Linum is the “true” flax long known to Europeans as the source of linen fiber; it in no way resembles Phormium and they are completely unrelated; Phormium is a monocot and Linum is a dicot.

Blue-eyed Grass (Sisyrinchium) and Black Mondo Grass (Ophiopogon nigrescens) are both iris family members with small lavender flowers, not grasses.

“Flowering Maple” is Abutilon, a shrub in the Mallow family. It is not even slightly related to the maples. Moss Rose (Portulaca) has nothing to do with either moss or roses. Lenten Rose and Christmas Rose are Hellebores- not particularly roselike, and not related to the roses. Evening Primrose is not related to, and does not resemble, the true primroses.

There are at least 30 different plants bearing names suggesting they are laurels; most are not related to English Laurel. Zonal Geraniums, which many people think “ARE” geraniums, are not true geraniums at all, but Pelargoniums- and differ from the true geraniums in flower color, foliage, and hardiness.

Some common names are so wrong they’re dangerous: Horse Chestnut (Aesculus spp) is not even related to the true chestnuts, and is poisonous.

Vaccinium is a large genus with many plants whose common names tag them as blueberries, while others are called huckleberries. There is no apparent major distinction between these groups- huckleberries may be blue; plants in either group may be evergreen or deciduous. For me, the common names Himalayan Huckleberry- (Vaccinium glauco-album) and Himalayan Blueberry (Vaccinium moupinense) are quite confusing. Which is which? The plants are very distinct; V. glauco-album is an evergreen dwarf with bluish leaves while V. moupinense is a large deciduous shrub with green to bronze leaves. But both have blue berries. What saves me is the Latin: “glauco-album” refers to the chalky, blue color of new foliage on that species.

Many people complain that botanical names are unwieldy, overly long, or hard to pronounce.  Yet, common names include a host of picturesque mouthfuls: Angel’s Fishing Rods (various species of Dierama), Kiss me Over the Garden Gate (Polygonum orientale), Love-in-a-mist (Nigella damascena), Love-in-a-puff (Cardiospermum halicacabum), Love Lies Bleeding (Amaranthus caudatus), Fetid Adder’s Tongue (Scoliopus bigelovii) and Old Man’s Beard or Traveler’s Joy (both names for Clematis vitalba).

The great thing about pronouncing botanical Latin is that there are no native speakers around to correct you, and many “Latin” names (e.g. washingtonensis, a species name applied to some plants found in the state of Washington) would not be recognizable to a native speaker of Latin, should we dig one up alive.  Revered California botanist Willis Jepson (1867-1946) remarked that the key to correct pronunciation was a tone of conviction.  Authoritative botanists do not always agree on plant name pronunciation.  The rule passed down among generations of botany students goes: “The correct pronunciation of any name is the one your advisor uses.”

Can you say Lobelia, Delphinium, Clematis, Rosa, Clarkia, Begonia, Geranium, Dahlia?  All these are botanical Latin. Many plants are known most widely by a common name that is identical or very close to the Latin one.

Pronunciation

There are some pretty consistent and some pretty complicated rules for pronunciation. The truth is that even botanical experts do not agree on pronunciations of many words. There are two general systems, “Academic Latin” and “Traditional English”- but most botanists I know use a hybrid of the two systems. In addition, most botanists and horticulturists who are comfortable with botanical Latin actually use some common names (e.g. for a plant that is the only representative of its genus in the region, and whose Latin name is unnecessarily long or silly.)

A couple of more or less consistent rules:

Every vowel is pronounced, particularly in the academic system:

Ex.: the suffix “oides” means “like”; in the academic system, it is pronounced with three syllables (oh-EYE-deez); in the traditional system it is pronounced with two syllables (OY-deez). The latter is most often heard.

“Ch” is most often pronounced as a hard “K”, though if it occurs in a name that comes from a modern personal or place name, it’s likely to be pronounced as in “cheese”.

The diphthong “ae” is pronounced “eye” as in aisle in the academic system, or in the traditional system as a long “e”; the latter is overwhelmingly more common.

The basic rule for where the stress falls in botanical Latin is that the accent depends on whether the second to last vowel or diphthong is long or short- FLOR- i-dus, for-MO-sa.

There are multiple exceptions, with assorted complicated reasons, including Greek origins and modern place or personal names. Most of the exceptions I have found turn out to be fairly self-evident to most people.

In truth, much of English (and French, Spanish, Italian and Portuguese) is derived from Latin (or Greek).  If you speak any of these modern languages, you use Latin or Greek-derived words every day and may already know the meanings of many of the roots from which botanical as well as everyday words in your language are derived. (For purposes of botanical discourse, Greek roots are subsumed under the general term “botanical Latin”.)

The binomial system was first set forth by Carolus Linnaeus (Carl von Linne) in 1753 with publication of Species Plantarum. (He also set forth a similar system for zoology.)

Prior to Linnaeus, Latin was the standard language of science throughout Europe, but a polynomial system was used that was unwieldy, not consistent, and did not provide unique names for species.

Though the context has changed, we continue to use Latin today in part because of long-established precedent, but also because of advantages conferred by using a “dead” language; as it belongs to no modern culture or country, the language is universal. (Equally inconvenient for everyone.) Unlike common names, which may vary from region to region and country to country, the same scientific name applies to the same plant everywhere, regardless of the native language of the speaker. Every plant species has one name that refers to that plant and no other.

From Wikipedia: “Botanical nomenclature is the formal, scientific naming of plants. It is related to, but distinct from taxonomy. Plant taxonomy is concerned with grouping and classifying plants; botanical nomenclature then provides names for the results of this process.”

The plant kingdom is divided into a hierarchy of groupings that represent evolutionary relationships, and can be visualized as an inverted tree (like a genealogy) with “kingdom” at the top and followed by phylum, class, order, and finally family, genus (plural “genera”), and species (singular or plural) at the bottom.  (And subspecies and variety.)

The plant kingdom is divided into vascular and nonvascular plants. The vascular plants include seed plants and non-seeded plants.

The seed plants include the Gymnosperms  (“naked seeds”) and the Angiosperms (the flowering plants).

Angiosperms (phylum Anthophyta or Angiospermae) are divided into two broad classes, the Monocots and the Dicots. These classes are based on number of seed leaves and are distinguished by some other characteristics as well. Monocots have a single seed leaf; they include the graminoids (grasses, rushes and sedges), the lilies and irises, and a few smaller mostly aquatic families. The Dicots have two seed leaves, and include most of our familiar broadleaf trees and shrubs, and a majority of perennials and annuals familiar to gardeners.

A family may sometimes contain only one genus, but usually contains several. We call plants by their genus and species names: the family Ranunculaceae includes numerous genera, including Ranunculus, Delphinium, Clematis, Helleborus, etc.  Each of these genera in turn usually includes numerous species.

Every plant species has a two-part name: e.g. Delphinium menziesii  - Delphinium is the genus name, menziesii is the species name (sometimes called the specific epithet).  Botanical names are always written in italics, with the genus name capitalized, other names all lower case.

Some species are further divided into a small number of subspecies or varieties. For example, Delphinium menziesii is divided into subspecies or varieties including menziesii, pallidum, and pyramidale.  The full name at this level is written Delphinium menziesii var. pyramidale, or Delphinium menziesii ssp. pallidum. Subspecies and variety designations tend to shift a good deal as new research and differing opinions emerge; they are usually not useful for non-specialists. Cultivar names are not the same as botanical varieties, although some cultivars are essentially commercially established versions of naturally-occurring taxa. A cultivar name is capitalized and set in single quotes.

In botanical listings, a full name includes the name of an “author” and often a date when the plant was named.

Wikipedia: “Botanical nomenclature is governed by the International Code of Nomenclature for algae, fungi, and plants (ICN), which replaces the International Code of Botanical Nomenclature (ICBN).”

The International Botanical Congress meets every six years, rotating countries. Botanists from all over and from various sub-disciplines meet and make decisions regarding the rules of the ICN and any major changes in taxonomy.

A new name may arise rarely on the basis of discovery of a previously unknown plant, but often on the basis of new information or a new understanding of the plant’s relationship to other taxa. Some changes arise due to disagreements between botanists along “party lines”- the splitters vs lumpers. A splitter sees smaller differences as more important, and may tend to differentiate plants at a finer-grained level, assigning subspecies designations, or separating out a previous subspecies as a separate species. Lumpers are more inclined to see those same variations as unimportant in taxonomic designation.

Any botanist can establish a name change via publication in an approved scientific journal. Prior to the age of DNA, most taxonomy had been established on the basis of close examination of morphology and then of chemistry, and for a few decades, isozymes (proteins). Most of the morphological classifications at the species level have stood up, with usually minor changes introduced by DNA analyses that provided a more finely-tuned concept of some plant relationships. Some major changes in family organization have happened in very recent years.

Example: Calamagrostis muiriana BL Wilson and Sami Gray

How we named a new species: C. breweri was long recognized as an alpine species growing on mountaintops in Oregon and California. It was considered to have two forms, the more southern form known to have a different number of chromosome sets (hexaploid vs tetraploid). The two types never grew close to each other, and the more southern form grew at distinctly higher elevations.

(Polyploidy- more than two sets of chromosomes- exists in some mammalian tissues, in some animals, and in many plants, up to 12 sets, at least.)

About a century ago, a botanist had suggested the two races might actually be different species, but frankly no one had been motivated to climb the respective mountains to find out. Herbarium specimens tend to wither and fade, so some morphological differences are harder to see.

Grown in a greenhouse, our two populations proved to be very distinct morphologically. Isozyme analysis (a way of comparing the molecular forms of certain metabolic proteins in plants) demonstrated that the two populations differed to an extent much greater than that considered to be the standard for species differentiation.

The southern population needed to be renamed. I chose the name Calamagrostis muiriana, after John Muir. The “iana” ending indicates that Muir actually saw the plant—we know from his diaries that he spent months in the area of Tioga Pass, where this grass carpets the meadows.

To establish the new species designation, we published our findings in an approved peer-reviewed journal (Madrona) and registered a “type” specimen in the herbarium at Oregon State University.

Botanical Latin has three genders- masculine (us) , feminine (a) , and neutral (um). Genus names are generally gendered, and endings for specific epithets must agree in gender with genus names- much like gendered adjectives and nouns in French or Spanish. Thus we have Delphinium pallidum (neutral) and Echinacea pallida, Rudbeckia hirta and Trifolium hirtum. This works—except when it doesn’t, due to exceptions for some suffixes and to other origins for the “a” ending.

Botanical names often give information about the appearance, geography, and uses of different plants. Sometimes, either the genus or the species name may refer to a famous person, often a botanist, who may have been associated with the discovery of the plant, or the name may have been conferred as a tribute to someone. (Chionodoxa luciliae was named by its discoverer, botanist Pierre Boissier, after his wife Lucile, in memoriam.) Those who name plants may not name them after themselves. (Linnaeus is the lone exception. He named Linnaea borealis after himself.)

Specific epithets often describe the origin. For instance, in many genera there are species identified with Japan: Camellia japonica, Pieris japonica and Fatsia japonica all happen to be horticulturally popular species within the respective genera.  Acer japonicum is one of the three main species included in the grouping “Japanese maples”.  All these different “japonicas” are unrelated and bear no resemblance to each other; they only have in common some connection with Japan.

There are names that refer to ethnobotanical uses (food, medicine, fiber), to ecological preferences (montane, seaside, forest etc.), to plant size, habit and life cycle, to color and other characteristics of vegetative parts, flowers, or fruit.

Other descriptive specific epithets may give clues about a plant’s overall size, habit (upright or sprawling, branched or branchless), leaf shape or texture, inflorescence type, etc.

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The family relationships embedded in botanical classification can provide hints about general plant characteristics. For example, most members of the Buttercup Family (Ranunculaceae) are more or less toxic, and are adapted to moist or shady environments. In the Sunflower Family (Asteraceae) most (but not all) plants are sun-loving; few are seriously toxic. Many have small, windblown or animal-dispersed seeds that make them successful weeds. They are often adored by slugs, but most have acrid flowers and foliage that make them almost universally deer-resistant. Plants in the Mint Family (Lamiaceae) are usually aromatic, often edible, and often spread quite aggressively via rhizomes or self-seeding. The Ericaceae (heathers) have small urn-shaped flowers, are often toxic, generally are strongly acid-loving and in need of excellent drainage.