Cultivar, Variety, Species, Genus: Botanical Terms Explained

Do the botanical terms used in plant naming confuse you? You’re not alone. Many gardeners, particularly beginners, avoid the seemingly complicated world of plant names. But gardening expert Madison Moulton is here to simplify them, explaining the differences between terms to help you become a better gardener.

Written by Madison Moulton Horticulture review by Sarah Jay Last updated: October 30, 2024 | 5 min read

A colorful assortment of vegetables with purple, green, and white heads nestled among broad, textured green leaves. The leafy greens have a wavy appearance, providing a lush background for the round and densely packed heads, which form a striking pattern in the garden bed.

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Horticulture is full of fancy botanical Latin phrases and technical terms that often put gardeners off. These botanical terms may seem incredibly complex, or worse, incomprehensible. But I promise plant naming is not as confusing as it seems.

We have Swedish botanist Carl Linnaeus to thank for this stress-inducing, mysterious plant naming system. Due to the volume of plants he dealt with over 250 years ago, Linnaeus wanted a simplified universal system to use in his book Species Plantarum. Thus, binomial nomenclature was born. Technically he wasn’t the first to use this system, but was the first to apply it consistently to the plant kingdom and later to the animal kingdom.

Understanding plant classification gives you vital knowledge that will help you better care for your crops. Unfortunately, common names are not consistent, so it’s hard to rely on them alone. Plus, they miss some of the clues involved in classification that provide greater knowledge of what we’re growing.

Let’s look at the botanical terms used in naming and classifying plants. I’m focusing on those that are useful to gardeners but know that there are many more groupings out there helpful to botanists too.

Family

A row of bright red radishes coming out of rich soil. — Plants with similar structures are grouped into families.

The first classification to be aware of is families. There are groupings above families, like orders and kingdoms, but for gardeners, this is typically as high as we need to go. Larger groupings don’t provide as much helpful information, so we start with this first level.

Plants with similar structures are grouped into families. This includes the shape of the leaves, the growth habit of the stems, or the shape of the flowers or seeds. They end with aceae and often start with genus names we can recognize, like Orchidaceae.

Let’s take broccoli as an example. The family name is Brassicaceae, commonly known as the brassica family. This family contains many other crops, including radishes and mustards, and ornamentals like alyssum.

Understanding that plants within the same family share characteristics is helpful in cultivation, particularly when it comes to problems like pests. When you understand which pests are likely to target a certain family, you can protect not only one species but all that fall within that group. Management methods are also generally similar between plants in a family.

Genus

A close-up of a broccoli plant showcasing a large, dense head surrounded by dark green, textured leaves in vivid detail. — There can be hundreds of genera within a family, or just a few, depending on the size.

Within a family, we have a genus. Or in plural, genera. The principle is the same as with families – plants are grouped together because they have similar characteristics. However, in the case of the genus, they have far more in common than plants within the same family.

There can be hundreds of genera within a family, or just a few, depending on the size. Back to the broccoli example, the genus name is Brassica (without the aceae at the end). Genera are always capitalized and italicized, too.

Many genera are a few hundred years old, initially named when binomial nomenclature was introduced. However, as scientists gain more information about the structure of plants over time, genera may change, or species within genera may move around.

For example, although many recognize the houseplant snake plant as Sansevieria, it was reclassified a few years ago into the Dracaena genus based on new molecular phylogenetic studies. It takes a while for gardeners to catch on (we’re clearly not fans of change), so you’ll often see plants still named using their old genus, or both genera listed as synonyms.

Species

A tight group of small white flowers with bright yellow centers, perched on slender green stems. The dense greenery in the background enhances the delicate texture of the petals, while the soft white contrasts sharply with the dark green foliage, creating a fresh, clean appearance in the garden. — They often give us clues to how the plant grows, where it was found, or who ‘discovered’ it.

A species name consists of two words as per binomial nomenclature (the ‘bi’ prefix gives that away). The first word refers to the genus, and the second is called the specific epithet.

Specific epithets identify specific characteristics that set a plant apart within a genus. They often give us clues to how the plant grows, where it was found, or who ‘discovered’ it. Some have Latin roots and others have Latinized Greek roots. Some are simply a version of the classifier’s name.

When you work with plants often, you’ll get to know the connections quickly. Some phrases, like ‘flora’ or ‘grand’ are easy to recognize already to help us decipher why a plant was named that way. Others are more complex. When it comes to plants named after people, plants ending in –ii are named after men, and –ae after women.

Here are a few examples of root words, prefixes, or suffixes:

Lact: Milky, as in Paeonia lactiflora
Aure: Gold, as in Epipremnum aureum
Phyl: Leaf, as in Arisaema triphyllum
Angust: Narrow, as in Lavandula angustifolia
Iber: From Spain, as in Iberis sempervirens
Maritima: From the seaside, as in Lobularia maritima

The genus name plus the specific epithet forms the species name. Back to broccoli, that is Brassica oleracea, or B. oleracea. The specific epithet roughly means vegetable, indicating what this species is typically used for.

Variety

Rows of tightly packed green and white heads, surrounded by large, dark green leaves that cradle the vegetables. The rounded, almost bumpy texture of the heads contrasts with the broad, smooth leaves that grow in a symmetrical pattern around the vegetables, showcasing an orderly and productive garden. — They are distinctly different from the main species in one or more ways but are still genetically related.

Varieties are different versions of a particular species (although not all species have different varieties within them). They are distinctly different from the main species in one or more ways but are still genetically related.

Varieties often emerge naturally without direct human intervention, but this is not always the case. This could be a random adaption, cross-pollination, or the result of evolution. Varieties are indicated by the abbreviation var. between the specific epithet and the variety name. Some varieties emerged through cultivation by humans.

Broccoli is Brassica oleracea var. italica, a variety of wild cabbage that was cultivated by humans. The botanical Latin terms are always in italics, while the var. remains standard.

What chiefly separates varieties from cultivars is that varieties are true to type, whereas cultivars may not be. Plant varieties are generally stable, allowing you to grow the same plant from seed. Those same characteristics that make it unique from the species will remain in the new plant. In other words, they grow true to type. The same is not true for cultivars, which we’ll look at next.

Cultivar

A rich burgundy vegetable head standing out against its silvery-green leaves with thick veins and a textured surface. The contrast between the dark, bold head and the pale green leaves adds a striking visual element, with the leaves spreading wide and providing ample coverage for the vibrant center. — The word itself is a combination of ‘cultivated’ and ‘variety’, indicating a subgroup of a species.

A cultivar is a single plant that has been bred by humans in a controlled environment and produces a specific characteristic. This botanical term is a combination of ‘cultivated’ and ‘variety’, indicating a subgroup of a species that was specially cultivated by people.

Plant breeders produce cultivars for many reasons, but the goal is improvement of some kind, either in growth habit or ornamental value. Some of these cultivars are a happy accident, though.

For example, there are cultivars of several vegetable crops that have been bred to be resistant to certain diseases, lowering the risk of ruining your harvest. Aggressive species have cultivars bred to be less invasive in the garden. Others are created to improve flower color or foliage patterns. The list goes on.

The key difference between a variety and a cultivar is cultivars are more difficult to reproduce from seed. They may be able to be cloned using vegetative propagation. Breeders often patent their cultivars before distribution, so it can actually be illegal to propagate a patented cultivar for resale.

Finishing off the broccoli example, there are many interesting cultivars to choose from, like ‘Di Cicco’ or the bright purple ‘Burgundy’. The cultivar name will appear after the species name, always within quotes and with capital letters. So the full name would be Brassica oleracea var. italica ‘Di Cicco’.