Land Plants

Land Plant Major Groups

There are Two Kinda Land Plants...

Non-Vascular or Vascular:

The major land plant groups follow evolutionary advances. The first of these was vascular tissue. Vascular tissue is specialized and allows some cells to conduct water and minerals, some to photosynthesize, and some to be structural. This evolutionary advancement allowed plants to grow taller, set down roots, and move away from the moist, dark places.

Non-Vascular (Bryophytes)

We'll start with plants whose ancestors are so old that they missed the vascular revolution. Non-vascular plants lack vascular tissue, but they may have organs that look and act similarly to vascular tissues. They may have stem, leaf, and root-like structures. They are evolutionarily older than the more complex vascular plants.

Habit: Small (a few cm high, less than 10 cm length/diameter).
Habitat: Moist or humid, usually shady
Reproduction: vegetative and/or spores

Non-vascular land plants include: liverworts, hornworts, mosses

Eliminating Characteristics: They are never woody, and never large (most are less than a few cm tall, and 10 cm or less in length or diameter). They never have flowers or seeds.

Non-Vascular Plants (Bryophytes)

There are Two Kinda Vascular Plants...

Spore or Seed:

The next major evolutionary change was the invention of seeds. Spores are dependent on water for propagation, but seeds allow propagation to occur in the protected space of the ovule. This allowed for further distancing from water sources, and the ovule protects the embryonic plant. Seeds turned out to quite an improvement.

Vascular Spore Plants:

Again we'll first address the plants that missed the seed revolution. Vascular spore plants include two classes. Lycopodiopsida are small plants, bearing spores in the crook (axil) between leaves and stem. They include quillwort, clubmosses, and spikemosses. In the case of quillwort, the spore sack is recessed into a fleshy part of the leaf base and covered. They are universally small plants, while they may spread around a bit, they rarely get more than 8" above the ground. Club and spike mosses both sport microphylls - tiny leaves that have only a single, unbranched vein. Polypodiopsida are larger plants, including some that are taller than 8'. Most species are grouped in the subclass Polypodiidae, which includes everything you'd call a fern (except one family, Marattiaceae, whose members all inhabit tropical and neo-tropical regions, and fall nicely outside of our regional scope). This class also contains the horsetails, which are fun, useful, and easy to identify, and the adders tongues, which are a small collection of very cool-looking plants.

Eliminating Characteristics: They never have flowers, seeds, or cones.

Vascular Spore Plants

There are Two Kinda Seed Plants...

Cone or Flower:

The earliest seed plants are called gymnosperms, technically 'naked seed'. Gymnosperms typically bear their seeds in cones. Usually, the cones take the typical woody form, but sometimes the cones look a lot more like berries or fruits than they do cones, so keep an open mind.

Cone Bearing Plants:

We'll first address the evolutionarily older group, the cone plants. These fall into four groups.

Conifers

The largest by far is the conifers, Pinopsida. These are mostly evergreen trees, occasionally shrubs with needle, scale, or awl-like leaves, and usually woody (but occasionally leathery, fruit-like, or berry-like) cones. Conifers are the dominant plant in non-tropical northern hemisphere forests.

Cycads

The next largest group is the cycads (Cycadopsida), which I'm admittedly obsessed with. These uber-cool palm-like plants have rosettes of pinnate fronds emerging from a woody trunk (which may be subterranean) and cones born in the center of the rosette. They look and feel like ancient plants (and in fact they are). They are quite common in landscaping because of their dramatic appearance, so once you know what to look for, you'll start to see them everywhere.

Ginkgo

Next is Ginkgophyta, a class whose sole surviving species is quite easy to identify by its distinctive fan-shaped leaves.

Gnetopsida

Last is a weird little group. The only genus in the class that falls within our regional scope is Ephedra. It's an odd-looking shrub seemingly made up of only green stems and branches - which are photosynthetic. The sometimes brightly colored cones are born in whorls around nodes in the stems and branches.

Eliminating Characteristics: They never have flowers, fruit, broad leaves, or spores.

Cone Bearing Plants

There are Two Kinda Flowering Plants...

Monocot or Dicot:

The terms monocot and dicot refer to the number of seed leaves a baby plant has: one (monocot) or two (dicot). While this doesn't immediately seem useful for identifying plants that are all grown up, it turns out that the groups do have persisting distinctive features.

Monocots:

Common features of Monocots - if your plant has any of these (and especially if it has more than one), start here:

Flower parts in multiples of 3 (3, 6, or 9 petals and/or sepals).
Parallel leaf veins.
Strappy linear leaves.
Leaves that form a basal rosette.
Aquatic plant with a rhizome.

Some recognizable types of monocots: grasses and grains (including cereal grains), orchids, lilies, palms, iris, birds of paradise, and bananas.

Dicots:

Common features of Dicots: flower parts in multiples of 4 or 5, usually branching forms, and complex leaf ventation. This is by far the biggest group of land plants.

All art credits on this page go to the open-source images from the Biodiversity Heritage Library.

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