Monsterous Taxonomy and Nomenclature

Roosie
Published on June 9th 2019
19
Some Monstera leaves
Have you found yourself desperately googling Monstera identification or Monstera species and then gotten lost in the contradictory mess of information out there? I have! Here's my evaluation from scouring the sources.
A close up of a Monstera leaf with many holes in it
A stunning mature leaf from a Monstera deliciosa plant
Plant taxonomy and nomenclature is a monstrously large subject. It's an entire scientific field revolving around the identification, description, naming and grouping of plants. In reality, taxonomy is an artificial system created by humans in an attempt to explain the world around us. It's not perfect and is subject to controversy. Botanical nomenclature is the official naming of plants.
In this system, every plant is given a two-part Latin name made up of a genus and a species, termed a binomial name. From the Latin name Monstera deliciosa alone you can deduce the genus the plant resides in (Monstera) and the species it has evolved from (M. deliciosa).
See the below article for more information on Latin naming:

Getting to grips with botanical Latin

Plant Evolution

All plants are in a continuous battle for light, water and space. They are constantly adapting to exploit and therefore thrive in their environment, with the overall aim of outcompeting other plants. The changes that help a plant survive are maintained through evolution, and these adaptions are shared across related species. This forms the basis of plant taxonomy.

Morphology

Historically plants (and everything else!) were categorised solely based on their morphology - what they look like. This is useful as generally, due to evolution, plants that look similar are usually related in some way.
A statue showing the evolution of man from monkey
A statue depicting the evolution of monkey to man

But convergent evolution

Convergent evolution is a process by which similar adaptions arise in unrelated groups of plants. This can throw a significant spanner in the categorisation of plants based solely on how they look.

Enter Science

As science continues to advance, we can learn vastly more about plants, and how they are related, using modern techniques such as DNA evidence and genetic studies. We are always improving our understanding of the plant world and how it is all connected. This can lead to some confusion as with more knowledge and understanding, the more we realise how wrong some plant classifications were!
A scientist in a laboratory with blue gloves and lab equipment

Reclassification and naming

We are now able to accurately deduce the genetic relationships between different plants and many have been reclassified as a result of this. However, it takes some time for that information to trickle down through the scientific community, to common garden knowledge. Often when plants are reclassified, the old classification becomes a synonym and some names stick!
Whilst changes to already learnt plant names can be irritating, this will stabilise over time and eventually lead to greater understanding and better plant care.

Now a real life, real confusing plant example!

Monstera is a hugely popular genus of plants, and many species are commonly grown as houseplants. Monstera leaves are large and showy, they change structure with age, and watching them develop can be thoroughly interesting. Their huge popularity makes trying to find accurate information online very difficult, with common names vs Latin flying all over the place!
Some green Monstera leaves
A stunning Monstera deliciosa specimen at Bristol Aquarium

Varieties, forms and cultivars

Variety is a taxonomic ranking below the species level which has arisen naturally in the wild. In botanical nomenclature varieties of plant are written using the abbreviation var.
Form is a secondary taxonomic ranking, below variety, which again has arisen naturally in the wild. Denoted by f. in Latin naming, for example Monstera deliciosa f. borsigiana. Plants classified as forms generally have a noticeable difference in their appearance.
Cultivars are a similar division to variety, below the taxonomic rank of species, except they do not occur naturally in the wild, but have been cultivated artificially by selective breeding. Cultivar stands for “cultivated variety” and cultivar names are capitalised and enclosed in brackets after the species name, for example Monstera deliciosa 'Thai Constellation'.
Artificial selection to produce cultivars occurs on a far smaller timescale compared to natural evolution. This is the basis of why many cultivars do not come true from seed and are best propagated through other methods, such as cuttings. The genetics of cultivars are generally not as reliable as true varieties, as they have been bred quickly to show specific characteristics like a particular colour of a flower or leaf patterning.
A green Monstera plant
A luscious green Monstera deliciosa

Monstera deliciosa vs. Monstera borsigiana

M. deliciosa is one of the most common Monstera species, and this is the big one most people look to grow as their prized houseplant. A similar plant, commonly known as Monstera borsigiana, is the most easily mistaken with this and it is frequently missold under the name M. deliciosa. It's a smaller version that looks similar, the main difference is in its growth.
Recent research has revealed it is not distinct enough to be considered a variety. It's termed a climbing form, denoted in Latin by f. and thus written as M. deliciosa f. borsigiana. The best way to tell the difference is to observe the habit of the plant, M. deliciosa grows in a more compact way, so the distance between the nodes is shorter compared to the climbing form, M. deliciosa f. borsigiana.
A close up of a green Monstera deliciosa var. borsigiana leaf
A Monstera deliciosa, you can just see the stem ruffles
Another method of identification that was popular for a while is to look for "ruffles" on leaf stems, near the leaf base. These ruffles indicate a true M. deliciosa species. This was always quite unreliable as an identification method. Now we know they are both actually the same species, but different forms, you see why! Additionally, these ruffles develop with age, so your plant may just not be mature enough to show them yet.

Variegated Monstera

The names Monstera variegata and Monstera albo variegata are not true scientific names, and thus they are not true plant species. These names are misused the most online, referring to two distinct cultivars that have been produced from the species M. deliciosa. So there is Monstera ‘Albo-Variegata' which has white variegation, usually covering up to half a leaf.
A white variegated Monstera deliciosa 'Variegata'
The white variegation in a Monstera ‘Albo-Variegata' leaf
Monstera 'Thai Constellation' is the other cultivar; it has creamy-yellow variegation. The pattern is in much smaller sections scattered across the leaves, reminiscent of stars in a galaxy, hence the starry-themed cultivar name.
A Monstera 'Thai Constellation' plant with creamy yellow variegation
Monstera 'Thai Constellation' with creamy yellow variegated leaves like a galaxy of stars.

Monstera obliqua vs. Monstera adansonii

A table with lots of green leaves from a Monstera adansonii plant
Monstera adansonii is also known as monkey mask
Pretty much anything labelled as Monstera obliqua won’t be this species but rather the very similar looking M. adansonii or a hybrid. M. obliqua is extremely rare, a botanical unicorn that has been documented in the wild less than 20 times ever. It has more hole than leaf, over 90% of the surface and is strikingly different from M. adansonii when you compare them directly.
The leaves of M. obliqua are extremely thin and smooth, comparable to a sheet of paper. Whereas in M. adansonii they are thicker and have a slightly rough texture. The holes also cover far, far less of the leaf area, around 50%.
A ture Monstera obliqua by Mick https://www.instagram.com/mickmitty/?hl=en
A true Monstera obliqua leaf with over 80% holes by @mickmitty

Buying and selling Monstera

It's due to the popularity of Monstera species as houseplants and shops struggling to meet this overwhelming demand that most of the confusion develops. Most shops typically care about sales above all else and usually, the correct naming and labelling of plants is not a priority.
It's really tricky when plants get super popular and when they are sold without proper research, the incorrect names proliferate and cause confusion for all!
Last updated: 10/10/19
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