Who Is Carolus Linneaus?

Today (May 23rd) is the birthday of Carolus Linnaeus a Swedish botanist born in 1707 and considered the Father of Taxonomy. Linnaeus developed the binomial naming system for plants in 1753 with the introduction of his book Species Plantarum. Binomial nomenclature is a system of naming living things by giving each a name composed of two parts. The first part of the name identifies the genus to which the species belongs; the second part identifies the species within the genus. A recent update has been the addition of varieties specific to the genus and species. This series of “names” are often called a “Latin name” because many of the identifiers are expressed in Latin grammatical forms.

The first letter of the genus is always capitalized, while the species is not (even when derived from a proper name such as the name of a person or a place). Both the genus and species are italicized. For instance, the binomial name of pink-flowering annual Phlox (named after the botanist Thomas Drummond) is written Phlox drummondii.

When a plant within the species differs from what is considered to be “typical”, a variety (sometimes called a subspecies) is generated. The variety is enclosed in single quotes, but if referred to as a subspecies it is not. For instance the white-flowering perennial Phlox is written as Phlox paniculata ‘David’ or Phlox paniculata subsp. David.

When referring to a plant in a genus when you don’t know what species it is, use the genus name followed by ‘sp.’. For instance Phlox sp. When referring collectively to some or all of the species in a genus, use the genus name followed by ‘spp’. For instance, Phlox spp.

Seems like a lot of rules and regulations for naming plants. So why bother? And why is it important?

It’s tempting to think that using the correct botanical name of a plant is arrogant and I have to admit some of the names are true tongue twisters. However, but when correct identification of a plant is necessary (as in the case of plants that will be consumed as food or medicine) safety requires that the correct plant be identified - and the only way to do that is to determine the botanical name.

The botanical name also gives clues about the plant. For instance, in the case of Phlox paniculata, the flowers are grouped in panicles, hence the specific epithet paniculata. Other clues relate to the color of the flower or the appearance of the appearance of the leaves. If alba is included in the name, you know it blooms white, while glauca indicates blue. Pubescent indicates a plant with hairy leaves, while glabrous is a plant without hairs of any kind.

Common names are descriptive and usually based on empirical evidence, but many are only recognized in a particular region and can create misunderstanding in other parts of the country. For instance Bluebells (Mertensia virginica) grown on the East Coast is a perennial that grows to 18-24” tall and has lovely blue flowers that hang in clusters, are bell-shaped and bloom spring through summer – but Bluebells grown in Texas (Hyacinthoides hispanica) is a bulb that grows 12” tall and has lovely blue flowers that are arranged in an upright that are arranged in a corymb and bloom only in the spring.

Determining proper names for plants is not an easy task. The International Code of Nomenclature (ICN) governs by an internationally agreed codes of rules. The generic name indicates a grouping of plants that all share similar characteristics; ideally evolving from one common ancestor. The species name is based on an analysis of plant morphology (physiological traits). Some of the characteristics studied include plant cells, tissues, vegetative structures, and surface structures. The most important characteristics are the reproductive organs (seed, flower inflorescence, arrangement of sepals and petals, plant embryo, presence of stigma or stamen, and fruit).

You may have noticed that the botanical names of some plants have changed. For instance, Spotted Leopard Plant was previously known as Ligularia tussilaginea ‘Auromaculatum’, but was re-named a few years ago as Farfugium japonicum ‘Aureomaculatum’. Same plant, but a different name.

Most name changes reflect a better understanding of the evolutionary lineage of the plant, or intensive study of the plant itself (stems, leaves, flowers, fruits). Many changes have been a result of the advance of technology that allows the comparison of the internal structure of DNA molecules.

There’s a lot more detail I could go into, but give consideration to starting to identify plants by their correct botanical name. With the mind-boggling number of plants available, it’s not possible to know all the botanical names, but why not try identifying a few in your garden? Consider it a birthday present to Carolus Linnaeus!