1. Plant Groups
In order to begin to classify plants, consider the structure by which the plant absorbs water.
Plants are either vascular or non-vascular. Vascular plants have tube-like structures that transport water from the roots to the stem to the leaves.
Non-vascular plants absorb water only through their surfaces.

2. Non –Vascular Plants
Non-vascular plants are plants that lack water-conducting vessels in their tissue known as tracheids.
Tracheids are located in the xylem, along with wood vessels.
They are the most important water-conducting vessels in seedless vascular plants and in gymnosperms.

3. Bryophytes
Bryophytes do not have a true vascular system and are unable to pull water and nutrients up from the ground at any significant distance.
Lacking this specialized system distinguishes bryophytes from ferns and flowering plants. It is for this reason that they are considered to be rather primitive plants.
They are regarded as bridge between water plants like algae and higher land plants like trees.
They are extremely dependent upon water for their survival and reproduction and are  usually found in moist areas like steams and forest floors.
They first evolved about 500 million years ago and were likely the earliest land plants.
The lack of vascular tissue limits their size, generally keeping them under 12 centimeters high. Roots are absent in bryophytes, rather there are root-like structures known as rhizoids.

4. Bryophytes (cont’d)
The word bryophyte refers to a group of plants that includes the mosses, liverworts, and hornworts. There are about 25,000 different species. 
Although  small in size, they are one of the largest groups of land plants and can be found almost everywhere in the world.
There are more species of bryophytes than the total number of conifer and fern species combined.
A common example of the Bryophytes are Mosses. 
Aside from lacking a vascular system, they have a gametophyte-dominant life cycle, i.e. the plant's cells are haploid for most of its life cycle.
Sporophytes (i.e. the diploid body) are short-lived and dependent on the gametophyte.

5. Bryophytes (cont’d)
These plants do not flower and as a result never produce seeds.
They reproduce by spore production
The process by which they produce spores is termed alternation of generations.
Liverworts and mosses have been found in the fossil record dating as far back as 300 million years ago - the Paleozoic era. As a result of an incomplete fossil record they are believed to have shared a common ancestry with the green algae.
Bryophytes have very distinct characteristics that has allowed for the development of three distinct classes - the Hepaticae (liverworts), Anthocerotae (hornworts), and Musci (mosses).

6. Tracheophytes (Vascular Plants)
The vascular plants have specialized transporting cells xylem (for transporting water and mineral nutrients) and phloem (for transporting sugars from leaves to the rest of the plant).
When we think of plants we invariably picture vascular plants.
Vascular plants tend to be larger and more complex than bryophytes, and have a life cycle where the sporophyte is more prominent than the gametophyte

7. Major evolutionary advances of the vascular plants.
Green Algae
Bryophytes
Tracheophytes
Development of the root-stem-leaf vascular system
nonvascularized body (thallus) that may be variously shaped,no leaves, shoots, or roots
no vascular system,leaflike structures are present, but lack any vascular tissue
early vascular plants are naked, rootless
vascularized stems,later vascular plants develop vascularized leaves, then roots
Reduction in the size of the gametophyte generation
wide range of life cycles, some gametophyte dominant, others sporophyte dominant
sporophyte generation dependant on gametophyte generation for food; gametophyte is free-living and photosynthetic
progressive reduction in size and complexity of the gametophyte generation, leading to its complete dependence on the sporophyte for  food ,in angiosperms, 3 celled male gametophyte and a (usually) 8 celled female gametophyte
Development of seeds in some vascular plants
no seeds
seed plants retain the female gametophyte on the sporophyte
Spores/Pollen
spores for resisting environmental degradation
Spores that germinate into the gametophyte generation
Spores that germinate into the gametophyte generation or spores that have the gametophyte generation develop within themselves

8. Ferns
Ferns are a very ancient family of plants: early fern fossils have been found before the beginning of the Mesozoic era, 360 million years ago.
They were thriving two hundred million years before the flowering plants evolved.
As we know them now, most ferns are leafy plants that grow in moist areas under forest canopy.
They are "vascular plants" with well-developed internal vein structures that encourage the flow of water and nutrients.
Unlike other vascular plants, where the adult plant grows  from the seed, ferns reproduce from spores and an intermediate plant stage called a gametophyte.

9. Ferns (cont’d)
There are two main differences between the ferms and other vascular plants. 
The first is that ferns are delicate plants that will only grow in areas which are moist.
They prefer sheltered areas on the forest floor, near streams and other sources of permanent moisture.
They cannot grow in hot dry areas like flowering plants and conifers. 
They do no have structures to prevent dessication - drying out.

10. Ferns (cont’d)
The second is linked to the first: ferns reproduce differently from the conifers and flowering plants.
It all has to do with moisture. Not just the moisture that allows the plant to live where it does, but the moisture that allows it to reproduce there. They have a more complicated method that depends on there being liquid water for the process to complete.
The sperm cell (male gamete nust "swim" to the egg).
As a result, they can only reproduce where there is sufficient moisture: reproduction  requires moisture.

11. Higher plants have a very "tough" reproductive system: the pollen from the male flower is very resilient, and the female flower nurtures the seed until it is ready to grow.
The seeds themselves are able, because of their structure, to wait for long periods in adverse conditions before they grow.
So the higher vascular plants have evolved to occupy nearly every place on the land surface of the earth.

12. Seed Plants
The seed plants are divided into two groups too. These groups are the gymnosperms and the angiosperms.
Gymnosperms are plants which produce seeds in cones.
One well-known type of gymnosperm is the conifer, which includes pine, fir and spruce trees.
In this province the Gymnoserms are our dominant vegetation. 
Angiosperms are plants which make their seeds in flowers thus we call angiosperms flowering plants.

14. Gymnosperms have seeds but no fruits or flowers
Gymnosperms have seeds but no fruits or flowers. Gymnos means naked, sperm means seed: in other words gymnosperm equates to "naked seeds".
Gymnosperms developed during the Paleozoic Era and became dominant during the early Mesozoic Era.
There are over 700 living species that are placed into four divisions.  These being:
Conifers,
Cycads,
Ginkgos, and
Gnetales

15. The largest, most widespread, and most familiar group are the conifers, Division Coniferophyta, that has about 550 species in 50 genera. T
hey include many familiar trees such as Douglas firs, Black Spruce and White Spruce. 
The other three Divisions of gymnosperms are much smaller and rather obscure.
Division Cycadophyta contains about 140 species of mainly tropical palm-like plants called cycads.
Division Ginkgophyta contains but one species, an 80 million-year-old evolutionary leftover known as the maidenhair tree.
Finally, Division Gnetophyta contains about 70 species, some with some very odd characteristics.

16. Cycads
Cycads retain some fern-like features, notably their leaf shape. 
Cycads were much more prominent in the forests of the Mesozoic than they are today.
Presently, they are restricted to the tropics.

17. Ginkgos
The ginkgos were also a much more prominent group in the past than they are today.
The sole survivor of this once hardy and varied group is Ginkgo biloba, the maidenhair tree.
Extensively used as an ornamental plant, Ginkgo was thought extinct in the wild until it was discovered growing natively in a remote area of China.
Ginkos have separate male and female plants. The males are more commonly planted since the females produce seeds that have a harsh odor.
Pollination is by wind.
Recently, Ginkgo has become the current herbal rave.

18. Conifers The conifers remain the major group of gymnosperms.
In this province and other regions of the world which possess similar climates and soil they are the dominant tree type. 
Their needle shaped leaves and other structures allow for survival in this type of environment.

19. Angiosperms
The angiosperms, were the last of the seed plant groups to evolve, and appeared over 140 million years ago during the later part of the of the Age of Dinosaurs.
All Angiosperms produce flowers.
Within the female parts of the flower angiosperms produce a diploid zygote and triploid endosperm.
Fertilization is accomplished by a variety of pollinators, including wind, animals, and water.
Two sperm are released into the female gametophyte: one fuses with the egg to produce the zygote, the other helps form the nutritive tissue known as endosperm.
The angiosperms produce modified leaves  that are grouped into flowers that in turn develop fruits and seeds.

20. There are approximately 230,000 known species
There are approximately 230,000 known species. Most have larger xylem cells known as vessels that improve the efficiency of their vascular systems.
The classical view of flowering plant evolution suggests they developed from  evergreen trees that produced large Magnolia-like flowers.
Recent Fossil evidence though appears to contradict this notion and a debate among botanists has ensued.
Regardless of their origin though it is agreed that the angiosperms underwent a significant adaptive radiation during the Cretaceous, and for the most part escaped the major extinctions that occurred at the end of the period