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.
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.
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:
||Rhodophyta, Magnoliophyta; Ascomycota, Basidiomycota|
|Subdivision (Subdivisio)||Either a distinctive character of the taxon or the name of an included genus followed by:
||Rhodophytina, Magnoliophytina; Ascomycotina|
|Class (Classis)||Either a distinctive character of the taxon or the name of an included genus followed by:
||Rhodophyceae; Magnoliopsida; Ascomycetes|
|Subclass (Subclassis)||Either a distinctive character of the taxon or the name of an included genus followed by:
|Order (Ordo)||Either a distinctive character of the taxon or the name of an included genus followed by:
|Suborder (Subordo)||Either a distinctive character of the taxon or the name of an included genus followed by:
|Family (Familia)||Basically a generic name plus:
There are 8 exceptions to the “family” classification: *see table below.
|Subfamily (Subfamilia)||Similar to family name, but suffix is:
|Tribe (Tribus)||Similar to family name, but suffix is:
|Subtribe (Subtribus)||Similar to family name, but suffix is:
|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|
|Leguminosae||Fabaceae||Bean family (Peas, beans, Palo Verde, Mimosa)|
|Guttiferae||Clusiaceae||St. Johnswort Family|