Naming & Classifying Plants

Previous: A Brief Evolutionary Timeline of the Plant Kingdom

To support familiarizing yourself with the trees of our urban environment, the examples provided below are mostly Chicago parkway trees that you would likely find on a walk around the streets of Chicago.

Scientific Naming

Very Broad > Very Specific

We typically discuss the Family, Genus, and Species the most.

• Kingdom – Plant
  • Division – Flowering Plants
    • Class – Monocots and Dicots
      • Order – Name ends in -ales
        • Family – Name ends in -aceae
          • Genus
            • Species

Example:

Bur Oak

• Kingdom: Plant
  • Division: Flowering Plant
    • Class: Dicot
      • Order: Fagales
        • Family: Fagaceae
          • Genus: Quercus
            • Species: Quercus macrocarpa

Binomial Nomenclature

Why use binomial nomenclature?

• used to make names more standardized
• one plant may have many common names
• one common name may refer to several different plants
• some common names can be misleading

Example:

Quercus macrocarpa

Quercus is the Genus, and macrocarpa is the specific epithet (not the species)

The Genus and specific epithet spoken or written together is considered the species (for example, Quercus macrocarpa is the full species name)

The binomial is also commonly referred to as the 'latin name' or 'botanical name'. I prefer saying botanical name since it's more accurate (as a lot of the naming comes from greek and not latin).

Varieties

Level below genus & species

Naturally occurring or botanical varieties that occur naturally, we also have cultivated varieties where there is human involvement in generating the variety.

Varieties that occur in nature are named like this:

• Thornless Cockspur Hawthorn
  • Crataegus crus-galli inermis
  • or
  • Crataegus crus-galli var. inermis

Cultivated Varieties are named like this:

• Magyar Ginkgo
  • Ginkgo biloba 'Magyar' (in single quotes)
  • Ginkgo biloba cv. Magyar (no quotes)

The Ginkgo above is a commonly chosen cultivar to plant on urban parkways in Chicago since it is an all-male cultivar (Ginkgos are dioecious, meaning that the male and female reproductive organs are found on different trees). The female trees produce seeds that have an 'undesirable' odor, so the preferred tree to plant are male cultivars.

Interestingly, some all-male cultivars have been found to change sex, presumably to facilitate reproduction, further reinforcing the notions that no, we cannot control nature, and yes, nature is quite queer :)

Cultivars can make plant ID more difficult as they may vary from the species description in floras and guides.

Hybrids - can occur naturally without any human intervention

Between two species in the same genus (often naturally occurring):

Platanus x acerifolia – (A large tree [[Chicago Parkway Trees |commonly planted on Chicago parkways]] that is a cross between non-native Asian planetree, Platanus orientalis and native Sycamore, Platanus occidentalis)

Side note: I've been noticing a lot of 'herbalists' and wellness influencers on social media talking about how hybrids are not natural and should be avoided (also they like to say that all hybrids are 'acidic' and therefore not 'alkaline' and therefore poison–yikes!...that is misinformation to the nth degree). This is simply made up to convice people to buy their products. First, the distinction between natural and non-natural is a bit of an illusion in the first place, but that's a whole different discussion. Second, hybrids occur naturally–which is to say, without human intervention. There are so many examples of naturally occurring hybrids.

Between two different genera (human intervention is usually required here):

Heuchera & Tiarella → x Heucherella

Trademark Names

Created by businesses, not botanical

Syringa pekinensis 'Zhang Zhiming' = Beijing Gold TM Peking lilac

Retail Nurseries, in order to use "Beijing Gold" have to pay a royalty, they could sell it under the name 'Zhang Zhiming', but unless they pays the royalty, the nursery cannot use 'Beijing Gold'

It seems that trademark names are utilized for species that defer to urban environments or captivity. For example, the Beijing Gold lilac is marketed for its ability to thrive in urban environments, tolerating acidic and alkaline soil, drought, and proximity to road salts.

This particular cultivar is native to China and introduced to the US through the Morton Arboretum.

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