Getting a grasp on the taxonomic plant code

Wow is there a lot to understand about plant classification.  At this point, it actually seems like an impossible amount.  But that’s just at this point…the beginning.

The beginning of our learning and doing adventure. These posts are really just our notes and journal entries for what we are learning and absorbing each day.  Some information may be incomplete or different from what you know.  We invite you to leave comments, share what you know, engage with us. These posts will also be updated as we broaden our knowledge and experience, and from feedback from plant lovers like yourself.

So taxonomy…why?

For me, knowing the taxonomy of a plant is the best way to learn about and understand the plants with which I am interacting.   By knowing its pedigree, I can know its characteristics and therefore have a better understanding of how to care for it.  Plus, I really want to know if I am getting a good deal or even buying the right kind of plant for my needs. So right now, my need is to wrap my head around taxonomy.

I found a lot of this initial information on these two sites: theseedsite.co.uk and herbarium.usu.edo.

The Plant Code

Plant names are determined by the International Code of Botanical Nomenclature, which lists a plants rank by groupings.

Principle ranks: The ranks to which every species belongs. The Code states that every plant belongs to only one species, and that every species belongs in a genus, every genus in a family, every family in an order, every order in a class, every class in a division (phylum), and every division in a kingdom.

Secondary ranks: Can be used, but not needed. Generally used to subdivide large groups in a principle rank. For example, a large family can be divided into tribes and similarly, a large species can be divided into varieties and a large variety into forms.

But wait, there’s more. Additional ranks can be added just below any principle or secondary rank by adding “sub”, or added just above by adding “super”.  For example, a subspecies is below species, but above variety.

Plant Ranking Descriptions

Below is a table listing the ranks in descending order from the highest “most broad reaching” rank, to the lowest “most exclusive” rank.  I will include the Latin names whenever possible, as I believe learning them will help me better recognize and classify unknown plants. Principle ranks will be bolded in green.

Rank (Latin) Summary and suffix Examples
Kingdom (Regnum) Names are nouns in the plural. Plantae, Animalia, Fungi
Subkingdom (Subregnum) not sure not sure
Division (Divisio) Either a distinctive character of the taxon or the name of an included genus followed by:

  • -phyta (algae, plants)
  • -mycota (fungi)
Rhodophyta, Magnoliophyta; Ascomycota, Basidiomycota
Subdivision (Subdivisio) Either a distinctive character of the taxon or the name of an included genus followed by:

  • -phytina (algae, plants)
  • -mycotina (fungi)
Rhodophytina, Magnoliophytina; Ascomycotina
Class (Classis) Either a distinctive character of the taxon or the name of an included genus followed by:

  • -phyceae (algae)
  • -opsida (plants)
  • -mycetes (fungi)
Rhodophyceae; Magnoliopsida; Ascomycetes
Subclass (Subclassis) Either a distinctive character of the taxon or the name of an included genus followed by:

  • -phycidae (algae)
  • -idae (plants)
  • -mycetidae (fungi)
Ophioglossidae
Order (Ordo) Either a distinctive character of the taxon or the name of an included genus followed by:

  • -ales
Magnoliales
Suborder (Subordo) Either a distinctive character of the taxon or the name of an included genus followed by:

  • -ineae
Malvineae
Family (Familia) Basically a generic name plus:

  • -aceae

There are 8 exceptions to the “family” classification: *see table below.

Magnoliaceae
Subfamily (Subfamilia) Similar to family name, but suffix is:

  • -oideae
Panicoideae, Rosoideae
Tribe (Tribus) Similar to family name, but suffix is:

  • -eae
Paniceae, Roseae
Subtribe (Subtribus) Similar to family name, but suffix is:

  • -inae
Andropoginae, Rosinae
Genus (Genus) A single word. It must be capitalized. Rosa, Ulva
Subgenus (Subgenus) You must state the name of the genus, the name of the rank, and capitalize the subgeneric ephithet. Only the generic name and the epithat are capitalized. Costus subg. Metacostus
Section(Sectio) As for subgenus. Ricinocarpus sect. Anomodiscus
Subsection (Subsectio) As for subgenus. Sapinum subsect. Patentinervia
Series (Series) As for subgenus. Arenaria ser. Anomalae
Subseries (Subseries) As for subgenus.
Species (Species) A binary combination consisting of a generic name and a single specific epithet (can be hyphenated). The specific epithet can sometimes be capitalized, but generally it is not. Poa pratensis, Scandix pecten-veneris
Subspecies (Subspecies) Name of the species followed by the name of the rank and the epithet of the rank. Stipa nelsonii subsp. dorei
Variety (Varietas) As for subgenus. Lycopodium inundatum var. bigelovii
Subvariety (Subvarietas) As for subgenus.
Form (Forma) As for subgenus.
Subforma (Subforma) As for subgenus.

Eight “Family” Exceptions:

Traditional name Alternate name English name
Gramineae Poaceae Grass family
Palmae Arecaceae Palm family
Cruciferae Brassicaceae Mustard family
Leguminosae Fabaceae Bean family (Peas, beans, Palo Verde, Mimosa)
Guttiferae Clusiaceae St. Johnswort Family
Umbelliferae Apiaceae Umbels (parsley,dill)
Compositae Asteraceae Daisy family
Labiatae Lamiaceae Mint family
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4 thoughts on “Getting a grasp on the taxonomic plant code

  1. That’s some information there! I love it! Thank you kindly for sharing. I do okay with just remembering their names. Sometimes I have to re-look it up. I look forward to learning more from you! Best, Koko 🙂

    Liked by 1 person

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