Curriculum 02

Plant Taxonomy and Field Identification

The universal language of plants — from scientific names to field identification

Section I — Foundation

Chapter 1: How Plants Are Named — Binomial Nomenclature

Why this matters: Common names are unreliable, regional, and sometimes dangerous. "Cedar" in Texas is actually a juniper. "Hemlock" could be a deadly herb or a harmless tree. "Bluebell" refers to dozens of unrelated plants. Scientific names are the one universal, unambiguous language of plants — used the same way in Texas, Mexico, Japan, and everywhere else. Learning to use them opens every field guide, research paper, seed catalog, and plant database on earth.

1.1 The Problem With Common Names

🖼

COMMON NAME FAILURES

From: 1.1 The Problem With Common Names

Image file: ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig01.png

Save image as ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig01.png in this folder, then replace this block with:
<figure><img src="../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig01.png" alt="COMMON NAME FAILURES"></figure>

1.2 The History of Plant Naming

🖼

BEFORE LINNAEUS (pre-1753)

From: 1.2 The History of Plant Naming

Image file: ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig02.png

Save image as ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig02.png in this folder, then replace this block with:
<figure><img src="../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig02.png" alt="BEFORE LINNAEUS (pre-1753)"></figure>

1.3 How Scientific Names Are Constructed

🖼

BINOMIAL NOMENCLATURE structure

From: 1.3 How Scientific Names Are Constructed

Image file: ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig03.png

Save image as ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig03.png in this folder, then replace this block with:
<figure><img src="../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig03.png" alt="BINOMIAL NOMENCLATURE structure"></figure>

What Species Names Mean

🖼

SPECIES EPITHET MEANINGS — common patterns

From: 1.3 How Scientific Names Are Constructed

Image file: ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig04.png

Save image as ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig04.png in this folder, then replace this block with:
<figure><img src="../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig04.png" alt="SPECIES EPITHET MEANINGS — common patterns"></figure>

1.4 Taxonomic Ranks Below Species

INFRASPECIFIC TAXA (below species level):

SUBSPECIES (subsp. or ssp.):
  A geographically or ecologically distinct
  population that can still interbreed
  
  Quercus fusiformis (Texas live oak)
  vs
  Quercus virginiana (coastal live oak)
  
  Some treat Texas live oak as:
  Quercus virginiana var. fusiformis
  (a variety of live oak)
  
  Written: Quercus virginiana subsp. fusiformis

VARIETY (var.):
  Smaller distinction than subspecies
  Often geographic or ecological variants
  
  Penstemon cobaea var. purpureus
  (a purple-flowered variety of wild foxglove)

FORMA (f.):
  Minor variation — usually just one characteristic
  (albino flowers, unusual leaf shape)
  Rarely important for field ID

CULTIVAR (cv. or 'Name'):
  CULTIVATED VARIETY — selected/bred by humans
  NOT found in wild
  
  Written with single quotes, NOT italicized:
  Rosa 'Belinda's Dream'
  Salvia 'Hot Lips'
  
  Cultivars may NOT breed true from seed
  (especially F1 hybrids — must be propagated
   vegetatively or bought fresh each year)
  
  IMPORTANT for seed saving:
  Save seed from species or open-pollinated varieties
  NOT from cultivars or F1 hybrids

1.5 The International Code of Nomenclature

🖼

RULES governing plant names

From: 1.5 The International Code of Nomenclature

Image file: ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig05.png

Save image as ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig05.png in this folder, then replace this block with:
<figure><img src="../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig05.png" alt="RULES governing plant names"></figure>

1.6 Synonyms and Name Changes

🖼

SYNONYMS — multiple names for same plant

From: 1.6 Synonyms and Name Changes

Image file: ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig06.png

Save image as ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig06.png in this folder, then replace this block with:
<figure><img src="../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig06.png" alt="SYNONYMS — multiple names for same plant"></figure>

1.7 Using Scientific Names in Practice

🖼

WHERE YOU NEED SCIENTIFIC NAMES

From: 1.7 Using Scientific Names in Practice

Image file: ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig07.png

Save image as ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig07.png in this folder, then replace this block with:
<figure><img src="../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig07.png" alt="WHERE YOU NEED SCIENTIFIC NAMES"></figure>

1.8 Building Your Personal Plant Name Reference

🖼

RECOMMENDED SYSTEM

From: 1.8 Building Your Personal Plant Name Reference

Image file: ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig08.png

Save image as ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig08.png in this folder, then replace this block with:
<figure><img src="../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig08.png" alt="RECOMMENDED SYSTEM"></figure>

Chapter Summary

🖼

BINOMIAL NOMENCLATURE

From: Chapter Summary

Image file: ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig09.png

Save image as ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig09.png in this folder, then replace this block with:
<figure><img src="../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig09.png" alt="BINOMIAL NOMENCLATURE"></figure>

📝 Interactive Quiz
0 / 39
Part A — True or False

1. The genus name is always capitalized in scientific plant names.

2. The species epithet (second name) is always capitalized.

3. Scientific names should be italicized when written.

4. A single plant species can have only one valid scientific name.

5. Common names are consistent across different languages.

6. The authority (author abbreviation) after a name indicates who first described the species.

7. "L." after a plant name means Carl Linnaeus first formally described it.

8. A synonym is an older or invalid scientific name that has been replaced.

9. Binomial nomenclature was established by Antoine Laurent de Jussieu.

10. The species epithet is sometimes a description of the plant's appearance.

11. Acer rubrum means "red maple" — rubrum is Latin for red.

12. When a genus name is abbreviated, only the first letter is used (e.g., Q. virginiana).

13. The International Code of Nomenclature governs plant naming rules.

14. Cultivar names are written in single quotes after the scientific name.

15. All plants in the genus Rosa are roses.

16. Two plants with the same species epithet but different genus names are unrelated.

17. Scientific names can be in any language.

18. A "cf." before a species name means the identification is uncertain.

19. Subspecies names add a third term to the binomial.

20. Understanding Latin and Greek roots helps decipher scientific names.

Part B — Short Answer

1. What are the two parts of a binomial name and what do each represent?

2. Why was standardized scientific naming necessary?

3. What does the authority abbreviation after a species name tell you?

4. What is a synonym in taxonomy?

5. Give three examples of species epithets that describe plant characteristics.

6. What is the difference between a species and a subspecies?

7. What is a cultivar and how is it written in a plant name?

8. Why might a plant's scientific name change over time?

9. What rules govern capitalization and formatting of scientific names?

10. Name five Latin/Greek roots commonly seen in plant names and their meanings.

Part C — Fill in the Blank

1. The system of two-part scientific naming is called nomenclature.

2. In the name Quercus virginiana, Quercus is the and virginiana is the __________.

3. The abbreviation "L." after a plant name stands for .

4. An older invalid scientific name that has been replaced is called a .

5. Cultivar names are written in quotes after the scientific name.

6. Scientific names are traditionally written in or underlined.

7. The Latin word "rubra/rubrum" means .

8. The Latin word "alba/albus/album" means .

9. A subspecies adds a name to the standard binomial.

Part D — Practical Exercises

Complete in the field. Check each off as you go.

1. Name Analysis: Look up the full scientific names of 10 plants on your property. For each, identify: genus, species epithet, and authority. What does the species epithet mean (use a Latin dictionary)?

2. Common Name Problems: Look up three plants that share the same common name (e.g., "cedar" — eastern red cedar, incense cedar, atlas cedar). What are their scientific names? Are they related?

3. Cultivar Reading: Visit a nursery or garden center. Find five plants with cultivar names in their labels (e.g., Rosa 'Knock Out'). Record: genus, species (if given), cultivar name. Are the cultivar names descriptive?

4. Name Decoding: Decode these species epithets using Latin/Greek: officinalis, vulgaris, sylvestris, canadensis, texensis, and pubescens. What do they mean?

5. Authority Research: Look up three plants with "L." as the authority. When did Linnaeus live? Look up one with "Torr." (John Torrey). When did he work? Why does Texas have many Torrey-named plants?

0 / 39 answered correctly

Practice Exercises

  1. Write the correct format for the scientific name of Texas bluebonnet: lupinus texensis torrey and gray
  2. A seed packet says "Salvia 'Hot Lips'". Can you save seed from this plant and expect it to grow true? Why or why not?
  3. Your field guide lists a plant as Yucca rupicola but an online database shows it as Yucca linearifolia. How would you find out which name is currently accepted?
  4. You find a plant labeled "wild onion" at a plant swap. Why is this common name potentially dangerous, and what do you need to confirm before eating it?
  5. A plant's species epithet is "officinalis." What does this tell you about the plant's historical use?
  6. Look up Sambucus canadensis on the USDA PLANTS database (plants.usda.gov). What is its native range and is it native to Texas?

Next Chapter → Plant Families — Learning to See the Patterns

Connections to Other Topics

🖼

→ C02 Ch02: Plant Families — genus and family relationships

From: Connections to Other Topics

Image file: ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig10.png

Save image as ../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig10.png in this folder, then replace this block with:
<figure><img src="../../../images/s01-foundation/c02-plant-taxonomy/ch01/c02-plant-taxonomy_ch01_binomial_nomenclature_fig10.png" alt="→ C02 Ch02: Plant Families — genus and family relationships"></figure>

Video Resources

Add video link
Add a video for this chapter
Paste YouTube URL above
Add video link
Add a second video
Paste YouTube URL above
To add videos: find the YouTube video ID (the part after ?v= in the URL), then add it to VIDEO_DB in convert.py and re-run the converter.