Plant Names Decoded: Genus, Species, and Cultivar Made Simple

Family, Subdivisions, and Class: Not Socioeconomics

Every plant has a taxonomic hierarchy—Kingdom, Division, Class, Order, Family, Genus, Species—but gardeners only need the last three for practical identification. Imagine memorizing Plantae Tracheobionta Spermatophyta Magnoliophyta Magnoliopsida Magnoliidae Ranunculales Ranunculaceae Helleborus orientalis just to buy a Lenten Rose!

Lenten Rose – Helleborus orientalis (Photo: KMAC)

The Big Three: Genus, Species, Cultivar

These are the functional identifiers. Even if pronunciation eludes you, their structure is logical. Most who use botanical Latin aren't showing off—it's simply the precise universal language of plants. (For etymology lovers, Botanary explains thousands of terms.)

How to Read Botanical Names

Like human names (Jane Doe, Mrs. John Doe), plant names have consistent patterns. Once you recognize the positions, it's straightforward.

Rules of Thumb

• Three names: Capitalized + lowercase + 'single-quoted' = Genus + species + cultivar.
  Echinacea purpurea 'Magnus'
• Two names: Capitalized + lowercase = Genus + specific epithet (together = species).
  Sorbus scopulina
• One unfamiliar name: Genus only. Euonymus (also a common name—confusing!)
• Capitalized + 'single-quoted' (two parts): Genus + cultivar (species omitted, often for hybrids).
  Dahlia 'Silentia'
• Abbreviated genus: E. purpurea for Echinacea purpurea. Use only when context is clear—E. purpurea could be Ipomoea purpurea (morning glory).
• Never standalone: Specific epithet (purpurea) or cultivar ('Magnus') alone—they're meaningless without the genus.

Echinacea purpurea 'Magnus' (Photo: Marilynbeth)

Common Name vs. Genus Name Traps

Searching by the wrong field yields zero results.

• Brugmansia: Common name = Angel's Trumpet. Search genus field for 388 results; common name field gives 4.
• Hibiscus: Both common and genus name—works either way.
• Carex: Genus = Carex; common name = sedge. Search "carex" in common name field = nothing.
• Crepe Myrtle: Common name = Crepe Myrtle; genus = Lagerstroemia. Distinct, but use the right box.

Brugmansia 'Adeline' (Photo: sibhskylvr)

Search Success Tips

• Separate genus and species into their respective fields. "Rosa rugosa" in one field fails; "Rosa" + "rugosa" in genus/species fields returns 24 matches.
• If a genus search in the common-name box fails, try the genus field.
• Italics and capitalization don't matter in search; spelling is everything.
• Use the general search if structured searches fail.

Pop Quiz: Identify the Parts

1. Arisarum proboscideum → Genus: Arisarum, Species: proboscideum
2. Hakonechloa macra 'Aureola' → Genus: Hakonechloa, Species: macra, Cultivar: 'Aureola'
3. Crinum powellii → Genus: Crinum, Species: powellii
4. Tricyrtis → Genus only
5. Impatiens niamniamensis 'Queen Congo' → Genus: Impatiens, Species: niamniamensis, Cultivar: 'Queen Congo'
6. I. pseudacorus → Genus: Iris (abbreviated), Species: pseudacorus

Master these patterns, and PlantFiles becomes a precision tool. The better we know our plants, the better we care for them.

---

Monkey image: Morguefile/Seeka.

Citation: Parry naming history: CSU Pomona