Bees Alive! is migrating - this is the new page...

On Plantae: Animals are something invented by plants to move seeds around.

Terrence McKenna

Kingdom Plantae was present in early, modern iterations of the classification of living things such as that developed by Linnaeus, and it still exists in the various six- and seven-kingdom systems that are used today. I am working from a generally accepted six-kingdom classification that weds the work of scientists such as Robert Whittaker, Carl Woese and Linnaeus. I'm talking about the plant kingdom as a backdrop to other pages on:

* plant cell anatomy

* plant anatomy

* pollination

Kingdom Plantae

Members of Kingdom Plantae share the following characteristics:

• They are multicellular.
• The cell walls are composed of cellulose.
• They absorb light and feed through photosynthesis.
• They possess no organs which allow movement.
• They reproduce both sexually and asexually as part of a biphasal life cycle commonly referred to as 'alternation of generations'.
• They have no central nervous system.

There is an incredible amount of disagreement about how to classify plants, how many ranks are needed, whether to include certain algae and fungi within the Plantae kingdom, and what to call the divisions. The bottom line is that if you are a student of horticulture or botany, or just someone interested in understanding the living world around us, trying to navigate the plant information world can be confusing.

I am not going to list and describe all the existing classification systems for Plantae here. We will focus on the Embryophytes or Land Plants, and leave out those plants that might better be included in Kingdom Protista. I will list 12 phyla within the Embryophyte division, and try to include synonyms and relevant links to terminology where possible. Click on the phyla below to see more detail on each ranking or just scroll down and keep on scrolling.

Non-Vascular Plants

These are plants that do not contain a system of specialized tissue allowing for the transport of water and nutrients throughout the plant (although certain plants may be able to transport water without the presence of xylem and phloem). Not having these tissues limits the size of these plants (seldom more than 7 to 8 inches for mosses and liverworts).

Non-vascular members of Plantae create their own food (autotrophic) and are multi-celled eukaryotes. They do not produce seeds, fruit or flowers.

Thumbnail photos provided as examples will open a new tab/window.

Class	Subclass	Superorder	Order	Photo
Andreaeobryopsida			Andreaeobryales
Andreaeopsida (granite mosses)			Andreaeles
Bryopsida (mosses)	Bryidae	Bryanae	Bryales Hedwigiales Orthotrichales Splachnales
		Hypnanae	Hookeriales Hypnales
		Ptychomnianae	Ptychomniales
		Rhizogonianae	Rhizogoniales
	Buxbaumiidae		Buxbaumiales
	Dicranidae		Archidiales Dicranales Grimmiales Pottiales Seligeriales
	Diphysciidae		Diphysciales
	Funariidae		Encalyptales Funariales Timmiales
Oedipodiopsida			Oedipodiales
Polytrichopsida			Polytrichales
Sphagnopsida			Ambuchananiales Sphagnales
Takakiopsida			Takakiales
Tetraphidopsida			Tetraphidales

With over 8,000 species, liverworts thrive under damp conditions. The body of a liverwort (thallus) has no distinct parts or organs (such as roots, stems or leaves) even though it might look like it does.

Class	Subclass	Order	Photos
Haplomitriopsida		Haplomitriales (Calobryales) Treubiales
Jungermanniopsida	Jungermanniidae	Jungermanniales
	Metzgeriidae	Metzgeriales
Marchantiopsida		Marchantiales Monocleales Sphaerocarpales

Some lovely photographs of liverworts and mosses by Jan Parmentier can be found here.

Like with the other Bryophytes, Hornworts enjoy damp growing conditions. The defining feature of a hornwort is its horn-shaped sporophyte (spore-producing appendage present during the life cycle phase when the plant reproduces asexually). This group includes approximately 100 species.

Class	Order	Photos
Anthocerotopsida	Anthocerotales Dendrocerotales Notothyladales Phymatocerotales
Leiosporocerotopsida	Leiosporocerotales	Leiosporoceros dussii is the only species

Vascular Plants (Tracheophyta)

Vascular plants or 'higher plants' are formed of specialized tissues, which allow nutrients to be transported throughout the organism. Vascular plants can generally be allocated to one of three main categories: seedless, plants with seeds, and plants with both seeds and fruit.

Seedless Plants

Considered 'fern-like' vascular plants, Psilotales, or whisk ferns, have enations rather than leaves, and lack roots, having rhizoids (like mosses) to anchor them. Ophioglossales houses Adder's Tongue (pictured to the left), moonworts, and grape ferns, plants producing either a single leaf at a time or 'spikes'.

Class	Order	Photos
Pteridopsida/Polypodiopsida    (leptosporangiate ferns)	Cyatheales (tree ferns)
	Gleicheniales
	Hymenophyllales (filmy ferns, bristle ferns)
	Osmundales (flowering ferns)
	Polypodiales (polypods)
	Salviniales (water ferns)
	Schizaeales

Plants with Seeds

Class	Order
Cycadopsida	Cycadales

Plants with Seeds and Fruit

Amborellales	A small tree or shrub found only in the South Pacific on the island of New Caledonia. Group contains only a single species: Amborella trichopoda.
Austrobaileyales	Approximately 100 species of woody plants and vines, the most well known being, perhaps, anise.
Ceratophyllum	Underwater-dwelling group of plants numbering at about 30 species. They are called hornworts, but this bears no relation to the 'hornworts' of the non-vascular phylum, Anthocerophyta.
Chloranthales
Eudicotyledonae
Magnoliidae
Monocotyledonae	With approximately 56,000 species, monocots include all flowering plants that have embryos with one cotyledon A third of the species in this group are orchids.
Nymphaeales	Water plants including water lilies. This group houses approximately 80 species.

Plantae: Terms and Vocabulary

Alternation of Generations

A term that describes a single life cycle that consists of two phases. The term applies to land plants as well as some algae.

Phase 1: multicellular diploid sporophyte

Meiosis occurs.

Phase 2: multicellular haploid gametophyte

Cotelydon

The first leaves that appear on a plant during the germination stage. They are present within the embryo. They are not true leaves (often called 'embryonic leaves' or 'seed leaves'), as the latter are formed during germination rather than during the embryonic phase. Monocotyledonae possess one cotelydon, while Dicotyledonae have two.

Embryo

An organism at the beginning of its development, an embryo is made up of cells with nuclei, which house genetic information. The embryo stage of a plant lasts until germination, the stage during which the plant emerges from its seed (or spore).

Eukaryotic Cell

Eukaryotic cells differ from prokaryotic cells in a few ways. They:

• Have a double-membrane-enclosed nucleus. Prokaryotic cells have no nucleus
• Possess linear DNA
• Have membrane-bound organelles that are independent from the cell membrane
• Have DNA organized into chromosomes
• Have more complex ribosomes than do prokaryotic cells

Gamete

Sex cell containing genetic material that joins with another sex cell during the fertilization phase of reproduction (e.g., ovum and sperm).

Meiosis

The process of cell division.

Photosynthesis

The process through which biological energy is created. Possible in members of Plantae, and some within Fungi and Protista (e.g., algae).

1. The organism captures energy from the sun.

2. The energy is converted to chemical form within the plant as ATP (adenosine 5’-triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate).

3. This stored energy allows the organism to convert water and carbon dioxide to oxygen and carbohydrates (especially sugars).

Ploidy

The number of sets of chromosomes present in a cell.

• Haploid Cell: a cell that contains one complete set of chromosomes. The actual number of chromosomes in this set is referred to as the haploid number or n. A gamete (sex cell) is a haploid cell.
• Diploid Cell: a cell that contains two complete sets of chromosomes (2n).

Vascular Tissue

Xylem: tissue composed mainly of dead cells that moves water and nutrients that can dissolve in water through a plant. Nutrient transport is upward from the roots through the plant and is unidirectional only.

Phloem: tissue composed mainly of living cells that moves nutrients through the plant. Much of what is transported are sugars and transport is multidirectional.

---

Return to Bees Alive! home from Kingdom: Plantae

Return to Biological Classification System from Kingdom: Plantae