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Why plants have those fancy long Latin names

Plant Taxonomy

Why plants have those fancy long Latin names.

Have you ever wondered why plants have those cumbersome long Latin names?  When you go to buy plants at your local nursery, why can’t you just ask for a Jasmine or a native Frangipani or a rose bush?  Well for starters, the person serving you would certainly ask; “What type of Jasmine?” as there are over 200 species of Jasmine. You may reply; “I’d like one of those Star Jasmines” and whilst the person serving you will know what plant you mean, the name you’ve used for this plant is not actually correct as a Star Jasmine is not a Jasmine (or Jasminum). This issue also applies to the Native Frangipani as it is not a Frangipani as horticulturists would know it.

The names for the plants I’ve used as examples are their ‘common’ names but in horticulture plants are referred to by their ‘botanical’ names (those long cumbersome Latin names) and each individual species of plant has its own botanical name. This avoids the confusion that using common names can generate. So the next time you go shopping for plants, instead of using their common names, try asking for ‘Trachelospermum jasminoides’ (Star Jasmine) or ‘Hymenosporum flavum’ (Native Frangipani) and not only will the person serving you know exactly which plant you’d like to buy but they are likely to treat you with a special kudos.

The way I’ve written the plants’ botanical names adheres to the International Code of Botanical Nomenclature that dictates they be written in italics with the first part of the name, the genus of the plant, having a capital and the second part, the species, having a lower case.

Is this starting to get confusing…?  Well, we can blame Taxonomy for this but ultimately it does all make sense.

Taxonomy is a science that finds, describes, classifies and names living things so how each individual plant species has come to be named (in their fancy long Latin names) derives from Plant Taxonomy.

The purpose of classification in Taxonomy is to group organisms according to characteristics that are common to each group and that scales down according the following internationally accepted Hierarchy of Biological Classification.

* Life is somewhat irrelevant as Taxonomy applies to ‘living’ things.

** Domain has not yet received international acceptance in the Hierarchy. Its purpose is to discern a new classification of organisms that are separate from those currently accepted and defined in ‘Kingdom’.

Kingdoms

As of 2015, there are seven (7) accepted Kingdoms:

  • Bacteria
  • Archaea
  • Protozoa
  • Chromista
  • Plantae
  • Fungi
  • Animalia

Several of these Kingdoms; Bacteria, Protozoa, Plantae, Fungi and even Animalia are of interest to horticulturalists but for the purpose of understanding Plant Taxonomy, we’ll focus on the Plantae Kingdom.

 

Plantae (plants)

Plantae or ‘plants’ are distinguished from the other Kingdoms by various characteristics:

  • Their cell walls are made of
  • They exhibit sedentary growth – whereas animals need to eat organic modules to grow, plants are able to obtain the energy to grow by converting the energy from light into organic energy. This process is called
  • Most plants are able to reproduce without needing to obtain chromosomes from another member of its species (how animals reproduce). This process is called

 

The number of types of plants that exhibit characteristics common to that group decreases as we proceed down the hierarchy until we reach the bottom group, species, where there will be only one plant.

The particular characteristics of the groups Phylum, Class and Order are confusing so we will avoid explaining how the different types of plants are assigned to these groups.  However, it is clear that at the highest levels of this hierarchy, plants are differentiated by how they reproduce.

 

Bryophytes (mosses)

Bryophytes are non-vascular land plants that reproduce via spores (ie. they do not produce flowers or seeds).  They also prefer moist habitats.  Mosses are a typical Bryophyte plant.

 

Polypodiophyta (ferns)

Polypodiophytes, commonly referred to as ‘ferns’, are vascular plants* that reproduce via spores. They are part of a larger group called Pteridophytes that also include horsetails (often treated as ferns), clubmosses, spikemosses and quillworts (these last three are collectively called lycophytes). Whilst they share and common identifiable features in that their plant bodies have identifiable roots, stems and leaves, polypodiophytes (ferns) are more closely related to seed plants than lycophytes and as they are the most numerous type of pteridophyte, they shall be investigated them separately.

*Vascular plants (Tracheophyta) are land plants with lignified tissues that conduct water and nutrients throughout the plant. (This is a similar function to the vascular system of an animal.) Lignin is a complex organic polymer that provides the rigidity in the plant.

 

There are about 10,560 known species of ferns and they can be considered specialists in challenging habitats, growing in places where the various environmental factors limit the success of flowering plants (angiosperms). Ferns are often found abundantly growing on the damp, light-restricted floors of rain forests, in bogs and swamps, on dry desert rock faces and on the branches and trunks of tropical trees where the species are epiphytes* that comprise almost one third of all fern species.

* An Epiphyte is an organism (including plants) that grows on the surface of another plant, such as its trunk or branches and derives its moisture and nutrients from the air, rain and the organic debris that accumulates around it or falls into its core such as some species of ferns.  Epiphytes tend not to affect their host plants negatively as they only use it for physical support (a location to support its growth).

Ferns feature the following identifiable characteristics:

  • Stems
    A fern’s stem is more correctly considered to be a rhizome* although for the majority of species they grow above ground. Epiphytic species of ferns have stolons**, creeping shoots from their stems that seek out a solid structure such as a woody part of a tree or large rock formation, they can attach to for the plant to continue its growth.
    Many species of ferns, such as the Dicksonia antarctica (Tasmanian tree fern) have erect, semi-woody trunks and can grow over 20 metres tall.*Refer to section on Monocotyledons, Stems and roots.
    ** Refer to section on Monocotyledons, Stems and roots. 
  • Leaves
    The green photosynthetic part of the fern is called the ‘frond’. New fronds, called ‘fiddleheads’, grow out of the top of the stem of the fern in a tightly curled configuration. The fiddlehead uncurls as it grows and develops into a frond.
    There are two types of fronds, Trophophyll and Sporophyll

    • Trophopyll fronds are similar to the leaves of a plant in that they photosynthesise and produce carbohydrates (sugars) that the fern uses to grow.
    • Sporophyll fronds are similar to trophophyll fronds in their shape, size and ability to photosynthesise but they also produce clusters of spores that the fern uses to reproduce. These clusters, called ‘sori’ are typically located on the rear (ground-facing) surfaces of the fronds.

 

Gymnosperms (conifers, cycads, ginkgo)

Gymnosperms are plants that produce their seeds in an unenclosed state.  The term ‘gymnosperm’ translated literally from the Greek means ‘naked seed’. The seeds of a gymnosperm develop on the surface of the leaves which then grow to become ‘cones’. The largest group of gymnosperms are Coniferae (conifers) followed by Cycadophyta (cycads) and Ginkgo of which there is only one species, Ginkgo biloba.

  • Coniferae
    Coniferae or ‘conifers’ are vascular, perennial woody plants, the majority of which are evergreen trees. They produce cones that contain seeds and as such they do not produce flowers. The leaves of most species of conifers are long and thin and referred to as ‘needles’.
    Within the Coniferae group there are eight (8) families, 68 genera (plural of genus) and 629 species that are currently recognised. Despite this relatively low number, Coniferae are ecologically important. They are the dominant plant covering large areas of land in the northern most regions of the Northern Hemisphere, areas that are subjected to snow-bound conditions for most of the year. As such they have adapted to these conditions with their conical shape and drooping limbs allowing them to shed snow easily and they are able to seasonally alter their biochemistry to avoid the liquid in their vascular systems from freezing.
  • Cycadophyta
    Cycadophyta or ‘cycads’ are plants that have a stout and woody (ligneous) trunk that may be only a few centimetres or several metres tall. They typically grow very slowly and can have quite long lifespans with some plants being known to be up to 1000 years old.
    Cycadophyta do not branch, rather, the leaves grow in a crown formation directly from the top of the trunk. As the leaves age they die and fall from the trunk to be replaced by new leaves growing from the top and centre of the trunk.  The leaves grow in a symmetrical formation from a central stalk, similar to the form of a feather.
    Another feature of Cycadophyta is that the species are either male or female (dioecious). They reproduce via pollination with their open seeds usually being pollinated by specific species of beetle.
    Palm trees (Arecaceae) are often confused with Cycadophyta, however, they are not even closely related and belong to different phyla.  The major difference is that Palm trees are Angiosperms and therefore produce flowers and fruit (which contains their seeds).

 

Angiosperms (flowering plants)

Angiospermae or Magnoliophyta is the most diverse group of land plants with 416 families, approximately 13,000 (known) genera and over 300,000 (known) species.  Similar to Gymnosperms, Angiosperms are also seed-producing plants but distinct from Gymnosperms, they produce flowers and fruit, the latter which contains their seed.

The term ‘angiosperm’ is derived from the Greek words angeion meaning ‘case or casing’ and sperma meaning ‘seed’ so literally it is a plant that produces its seed within a casing, ie. its fruit.

Angiosperms are divided into two distinct groups, Monocotyledons and Dicotyledons. A ‘cotyledon’ is the significant part of the embryo within the plant’s seed.  It is the embryonic leaf that first appears in a germinating seed with plants producing one leaf referred to Monocotyledons and plants producing two embryonic leaves referred to as Dicotyledons.

  • Monocotyledons
    Monocotyledons or ‘monocots’ as they are commonly referred to consist of approximately 60,000 species. The largest family in the monocotyledon group is Orchidaceae (Orchids) with approximately 20,000 species.  Another 10,000 species (approximately) belong to the Poaceae family (grasses) which economically are the most important family of monocots.
    In agriculture, the majority of harvested crops are These include not only the major grains; wheat, rice, barley and corn but also grasses for stock feed (hay), sugar cane and bamboos.  Other important monocotyledon crops include bananas, various species of palm (date, coconut), gingers, asparagus, pineapple, leeks, onions and garlic.  Many bulb plants grown for their flowers are also monocotyledons. These include lilies, daffodils, irises and tulips.
    Monocotyledons are distinguishable from Dicotyledons primarily in terms of uniformity. With regards to the organisation of their shoots (how they grow), their leaf structure and floral configuration, they exhibit more uniformity than dicotyledons.
    • How they grow
      Most families of monocotyledons lack the ability to form a ligneous (woody) trunk and therefore tend to be most herbaceous*.
      However, some families of monocotyledons do grow quite tall such as Arecaceae (Palms), Bambusoideae (Bamboo) and Agave but the configuration of the cell structure in their central trunk is quite different from dicotyledons that grow into trees. In the latter there is a lateral configuration of cells that repeats for the length of the trunk (cambium). This noticeable in the long vertical lines that appear in the tree’s bark.  Monocotyledons do not have this ability so their trunks exhibit a series of broad rings, one on top of the other, that proceed the length of the trunk.*Herbaceous plants are vascular plants that lack a persistent woody stem. As such these plants tend to be low growing with their leaves growing on soft green stems that shoot directly out of the ground.

    • Leaf structure
      Monocotyledons have leaves that are long and narrow and tend to be sheathed around the stem at their base. The leaf veins run in parallel along the length of the leaf.
    • Flowers
      The petals on the flowers of monocotyledons are configured in multiples of three and the period of flower opening (anthesis) is usually short-lived.
      About two thirds of monocotyledons are pollinated by insects and animals (zoophilous) and as such need to exhibit showy flowers as a means of advertising to their pollinators.
    • Stems and roots
      A cambium in a dicotyledon is a layer of tissue that provides partially undifferentiated cells for the growth of the plant. These cells form in parallel lines and allow the plant to grow in diameter as it grows in height. The cambium also exists in a dicotyledon’s roots and combined with the cambium in the trunk supports the tall growth of trees.
      Monocotyledons do not have a cambium so their primary root isn’t able to grow sufficiently, penetrating deep and broadly through the soil, to maintain the plant. Therefore they have developed adventitious* root structures and horizontally growing stems and shoots, rhizomes and stolons to support their growth and propagation.
      A rhizome is the main stem of the plant that grows horizontally under the surface of the soil. As it grows, it develops nodes at short intervals that sprout roots and generate new shoots that penetrate upwards through the soil. These shoots are not new plants but new growth from the original plant, similar to a tree growing a new branch.
      If a rhizome is separated from its original plant, it will be able to grow a new plant as it stores starches, proteins and other nutrients required to support the growth of a new shoot.
      Due to this ability to store starches and proteins, some rhizomes are grown for agriculture such as ginger, turmeric, galangal and the lotus root.
      Stolons or ‘runners’ are distinct from rhizomes in that they are sprouts from an existing stem and grow along the surface of the soil or just below it.  They also develop nodes that sprout roots as they grow but from each node grows a new plant.
      Another distinctive feature of monocotyledons is that their vascular bundles are scattered through their stems whereas in dicotyledons they are structured in a ring in the centre of the stems and trunk of the plant.
  • Dicotyledons
    Dicotyledons or ‘dicots’ as they are commonly referred to, comprise approximately 70% of angiosperm species or approximately 200,000 in number. Distinct from monocotyledons, their seeds feature two cotyledons, therefore forming two embryonic leaves upon germination.Their distinctive features are as follows:

    • Flowers have petals in fours or fives
    • Vascular bundles are structured in concentric rings in the centre of the stems
    • Leaves tend to be broad with veins emanating outwards from the central stem of the leaf
    • Roots develop from the radicle* root.

The largest group/class of dicotyledons is eudicots with the other major class being magnoliids.

* The Radicle root is the first root to emerge from the seed as it germinates and grows down into the soil. As the seedling grows, new roots develop off the radicle root.

  • Eudicots
    Eudicots are distinguished from all other angiosperms by the structure of their pollen*. Their pollen grains feature three pores whereas all other angiosperms feature only a single pore in their pollen.
    Many familiar plants are eudicots including, sunflowers, apples, cabbage, dandelion, maple and macadamia.  Most common leafy trees are also* Pollen is a powdery substance produced in the flowers of angiosperms. It is analogous to male sperm cell.  During the process of pollination, it is transferred by a pollinator, usually an insect or small animal, to the compatible ‘pistil’ or female cone of a flower on another plant of the same species.  Plants have protective mechanisms to prohibit self-pollination.
  • Magnoliids
    Magnoliids is a group of approximately 9000 species of angiosperms including magnolias, cinnamon, nutmeg, bay laurel, black pepper and avocado.
    This group shares some its distinctive features with monocotyledons in that it has flowers with petals in threes and pollen with a single pore. However, most of its other distinctive features are consistent with

 

So how do plants get their fancy long Latin names?

Plant Taxonomy classifies and then ranks the different types of plants according to characteristics that are common to each group. As we proceed down the hierarchy, the characteristics defining the plant become more specific (eg. an angiosperm that is a dicotyledon (eudicot) and produces shrubs and trees) until we reach the second last rank, ‘genus’, from which a plant derives the first part of its botanical (fancy long Latin) name.

A genus is a tight grouping within a ‘family’ (the rank immediately above genus) of plants where there is a distinctness to their ecological characteristics.  A genus can also be considered a plant’s generic name such as ‘Magnolia’.

The second part of a plant’s botanical name is derived from the final group in the Plant Taxonomy hierarchy, Species, for which there will be only a single member.  This ensures that every species of plant identified has a unique (botanical) name.

Let’s examine how Plant Taxonomy can be applied to some of my favourite plants.

Asplenium australasicum (Bird’s nest fern)
Class:
Polypodiophyta (ferns)

Genus: Asplenium
Asplenium
is a genus of approximately 700 species of ferns that have commonalities in their molecular structure, their DNA sequences, chromosome count and the structure of their rhizomes.

Species: australasicum
Asplenium australasicum is a species of fern that is native to eastern New South Wales and Queensland. It grows as either a shrubby plant on the floor of rain forests or as an epiphyte growing off the branches of tropical trees.  It is distinctive from other species of fern in that its fronds form as single, firm, leathery leaves of a light-green colour that are capable of growing up to lengths of one metre.

Scaevola aemula (Fairy fan-flower)
Class:
Angiosperms (flowering plants)
Class: Eudicots (dicotyledons)

Genus: Scaevola
Scaevola
is a genus of flowering plant of approximately 130 species, 80 of which are native to Australia.  The characteristic that is common to the genus is that their flowers feature five petals and look as if they’ve been cut in half, ie. the flower does not have a full round shape. Consequently, the name ‘scaevola’ is derived from ‘left-handed’ in Latin.  Another characteristic to the genus is that they are low-growing with species growing either in a prostrate fashion or into small shrubs.

Species: aemula
Scaevola aemula
is a low-growing herbaceous plant, native to southern Australia that produces blue or white flowers growing along stems with small green leaves.  The plant grows in dry and sunny habitats and as such is often used as a groundcover.

 

Waterhousea floribunda (Weeping lilli pilli)
Class:
Angiosperms
Class: Eudicots

Genus: Waterhousea
Waterhousea
is a genus of flowering plants (trees) that belongs to the Myrtaceae (Myrtle) family. Whist there are only four species in the Waterhousea genus, they share characteristics common to the Syzygium genus of Myrtaceae, most of which bear the common name ‘Lilli pilli’.

Species: floribunda
Waterhousea floribunda
is tree that is native to the rain forests of eastern Australia. It is a large tree that can grow up to 30 metres tall with trunk diameters up to 75cm. It features small white flowers and then develops pink or green berries when pollinated inside which is only a single large seed.

 

Magnolia grandiflora (Southern magnolia)
Class:
Angiosperms
Class: Magnoliids

Genus: Magnolia
Magnolia
is a large genus of flowering plants with over 200 species. It is an ancient genus, appearing on earth before bees, therefore the flowers evolved to encourage pollination by beetles. (Fossilized specimens have been found that date back 20 million years.)  The genus is comprised of large, spreading trees and shrubs of both evergreen and deciduous species. They feature large flowers, either bowl-shaped or star-shaped and with 6 – 15 petals.

Species: grandiflora
Magnolia grandiflora
is a large tree, growing to almost 30 metres in height, that is native to southeastern United States.  It is an evergreen tree with large, stiff and leathery dark green leaves up to 20cm long and 12cm wide that also feature a furry brown underside. The flowers are large and white, growing up to 30cm in diameter, with 6 – 12 petals. They appear on the tips of new branches in late spring.

 

 

 

 

 

 

Ask Malcolm

Malcolm has years of experience in horticulture and gardening and not only has an extensive knowledge of plants, including their propagation but also has experienced and overcome practically every issue that could confront the home gardener.

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