The short version: The Latin on a seed packet is a two-part name, genus then species, that identifies one plant exactly no matter what it is called in your street, your grandmother's kitchen or another country. Solanum lycopersicum is a tomato everywhere; "spinach" might be four different plants. The first word groups related plants, the second picks out this one, and extras such as subsp., var. or a cultivar name in single quotes narrow it further, while an x marks a hybrid. Learn a couple of dozen common species words and the name starts telling you what the plant is like. Botanical names matter because growing advice, allergies, seed saving and the biosecurity rules for Western Australia and Tasmania all depend on knowing precisely which species is in the packet.
Nobody needs Latin to grow a radish. But every gardener eventually meets the problem the Latin solves: two neighbours arguing about whether silverbeet is spinach, a recipe that calls for cilantro, a packet of "pepper" that could be a chilli, a capsicum or a vine, or a growing guide from another country describing a plant that only shares a name with yours. This is a plain guide to how the names work.
Two words that mean one plant
The system was formalised by the Swedish naturalist Carl Linnaeus in 1753 and every plant name still follows it. The first word is the genus, a group of closely related plants, and it is always capitalised: Solanum, Brassica, Allium, Cucurbita. The second is the species epithet, written in lower case, which picks out one species within the genus: Solanum lycopersicum is the tomato, Solanum tuberosum the potato, Solanum melongena the eggplant. Together they are italicised when printed, and after the first mention the genus is often shortened to its initial, so Salvia officinalis becomes S. officinalis. The second word never stands alone, because the same epithets turn up across dozens of unrelated genera: sage, lemon balm and calendula all carry the epithet officinalis.
Above the genus sits the family, whose name ends in -aceae: the tomato is in the Solanaceae, the cabbage in the Brassicaceae, the onion in the Amaryllidaceae. Families matter to gardeners because relatives share pests, diseases and feeding habits, which our guide to vegetable plant families explains.
Below the species: subspecies, varieties and cultivars
Within a species there are wild variants and bred ones, and the way the name is written gives you clues.
- subsp., var. or f., in plain type, introduce a botanical subspecies, variety or form, whose own name goes in lower-case italics: Beta vulgaris subsp. vulgaris covers beetroot and silverbeet.
- A name in single quotes, capitalised and not in italics, is a cultivar, a variety selected or bred by people: Solanum lycopersicum 'Black Krim', Cucurbita maxima 'Queensland Blue'. The convention is set by an international code for cultivated plant names, which is why you will not see double quotes or the abbreviation cv. on a careful label.
- A Group name collects cultivars that share a set of features, written after the species: Brassica oleracea Italica Group is broccoli, the Capitata Group is cabbage, the Acephala Group is kale. It is the honest way to say that all of these are one species.
- A multiplication sign between the names (properly ×, though it is often typed as a plain x) means a hybrid between two species. Peppermint is usually described as Mentha × piperita, a cross between watermint and spearmint.
Two more things appear on modern labels. A trade designation is a marketing name that sits alongside the true cultivar name, and in Australia a new variety can also be protected under Plant Breeder's Rights, which is administered by IP Australia and is a legal registration separate from the botanical name.
Why common names let you down
Common names are local, and the same word means different plants in different places. "Spinach" in Australia may be true spinach (Spinacia oleracea), silverbeet (a Beta vulgaris cultivar group), New Zealand spinach (Tetragonia tetragonoides) or Malabar spinach (Basella alba), four plants from three families with different seasons and different cooking. "Pepper" covers capsicum and chilli, both Capsicum species, and the black pepper vine, Piper nigrum, which is no relation. The reverse problem is just as common: one plant, many names. Salad rocket and arugula are both Eruca sativa, though wild rocket is a different plant, Diplotaxis tenuifolia; coriander and cilantro are Coriandrum sativum; zucchini and courgette are Cucurbita pepo; eggplant and aubergine are Solanum melongena; swede and rutabaga are Brassica napus. When you read a growing guide from Britain or America, the botanical name is the only way to be sure it is talking about your plant.
What the species word tells you
Many epithets are plain descriptions, and once you know a few the name becomes a hint about the plant. A short glossary of the ones you will meet on seed packets:
- officinalis: used in medicine or the old apothecary trade (sage, lemon balm, and rosemary as Rosmarinus officinalis).
- sativus, sativa, sativum: cultivated (garden pea, oats, garlic, rocket).
- vulgaris, vulgare: common (beetroot, thyme, oregano).
- esculentus, esculenta: edible (okra, taro).
- annuus, annua: annual (sunflower, sweet Annie).
- perennis: perennial (English daisy).
- maxima, maximus: largest (Queensland Blue pumpkin is Cucurbita maxima).
- alba, rubra, purpurea, aurea: white, red, purple, golden.
- japonica, chinensis, australis: from Japan, from China, southern (not necessarily Australian).
- tomentosa, glabra: hairy, smooth.
- repens: creeping. nana: dwarf. giganteus: giant.
Pronunciation is not standardised and there is no wrong way as long as you are understood. Botanists in different countries say the same names differently.
When the name changes
Names are not carved in stone. As botanists learn more about how plants are related, especially from DNA, some plants are moved and renamed, and the old name becomes a synonym that lingers on packets and in books for years. The tomato was Lycopersicon esculentum for most of the twentieth century and is now Solanum lycopersicum. Rosemary, Rosmarinus officinalis on every older label, was moved into the sage genus in 2017 and Kew now lists it as Salvia rosmarinus, though the Australian Plant Census still accepts Rosmarinus officinalis, so expect to see both. Internationally the beet family Chenopodiaceae has been folded into the Amaranthaceae, and the onion family Alliaceae into the Amaryllidaceae, but the Australian Plant Census still keeps both older families, so you will meet both names. None of this changes the plant or the growing advice; it only changes the filing.
Where to check a name in Australia
The Australian Plant Name Index and the Australian Plant Census, maintained with the Australian National Herbarium, are the standard references for plants that are native to or naturalised in Australia: the Census gives the accepted name and the Index records every name and synonym. VicFlora (Royal Botanic Gardens Victoria) and PlantNET (Royal Botanic Garden Sydney) cover their states, and Kew's Plants of the World Online is the main international reference for crops that do not grow wild here. A quick search of any of them settles most arguments.
Why the botanical name matters
- Growing advice: a guide for Brassica rapa is not a guide for Brassica oleracea, even though both have "broccoli" in some of their common names.
- Safety: allergies, edibility and toxicity are properties of a species, not of a common name. An ornamental cultivar of an edible species is not automatically edible, and a plant that shares a common name with a food plant may be nothing like it.
- Seed saving: most crossing happens within a species. Knowing that kale, cabbage and broccoli are all Brassica oleracea tells you they can cross with each other and rocket cannot.
- Biosecurity: Western Australia's seed import rules call for paperwork that identifies the genus and species of what is in the packet, and Biosecurity Tasmania asks for imported seed packets to be labelled with both the common and the botanical name. The Latin on the packet is part of what gets your order through.
Frequently asked questions
Do I need to learn botanical names to garden well?
No. Common names are fine for everyday use. The botanical name is a tool for the moments when a common name is ambiguous: reading overseas guides, checking edibility, saving seed or sending seed interstate.
Why are some names in italics and some not?
The genus and species are Latin and go in italics. A cultivar name is a modern name in a modern language, so it sits in single quotes without italics: Lactuca sativa 'Buttercrunch'.
What does the x mean in a plant name?
A hybrid between two species; it is properly a multiplication sign. Mentha × piperita, peppermint, is a cross of two mints, and the name does not tell you which two, so treat a hybrid as a plant in its own right.
Why did the name on my old seed packet change?
Botanists reclassified the plant, usually after DNA studies showed it belonged in a different genus or family. The old name is now a synonym. The plant, and the way you grow it, are unchanged.
Read the Latin as a label rather than a test and it becomes one of the most useful things on the packet. The Australian Plants Society NSW has a friendly introduction to native plant names, and the Australian Plant Name Index is the place to look up a plant that grows wild in Australia.
Related growing guides
- A beginner's guide to vegetable plant families
- Forgotten heritage vegetables worth rediscovering from seed
- How long do seeds last? Storing seeds and testing if they still grow
Check the botanical name when you browse our herb seeds, vegetable seeds and flower seeds.