FINALLY - A Good Way to Classify Plants

I found a really good slideshow at:
http://www.slideshare.net/geonyzl/classifying-plants-based-on-climate-and-habitat-331230

It really helped me decide how I was going to do Part B of my experiment - I needed "different types" of plants, but I wasn't sure which classification method to use so that they would be "different". So I've decided to get rid of the flower, cactus, and "different types of plants" in that sense; and I have firmly resolved to classify the plants by the way they reproduct.

This is because the slideshow helped me realise that if I classify plants by their habitat, one or more of the test plants will always be at a disadvantage because I'm only growing them in one habitat - that is, if I grow a flower and a cactus in the same place (my backyard), the cactus will probably grow better than the flower because the cactus is very efficient in the use of water (since it comes from a desert habitat), whereas the flower is not as efficient at using water. Since I will give each plant an equal amount of water, the flower would thus would be at a disadvantage.

Also:
- Classifying plants by life span would be pointless, since I'm only growing them for about 2 and a half months, and the effect of the allelochemicals would not be aided/inhibited by life span.
- Classifying plants by "growth habit" or their structure (woody = trees; or herbaceous = green and leafy) would be pointless because I cannot grow trees in the short time period that I have, so I cannot compare the effect of allelochemicals on trees vs. the effect on green, leafy plants.
- Classifying plants by climatic adaptation would be pointless because I'm only going to grow the plants in one climatic area, meaning that one or more plants would always be at a disadvantage, just as in the habitat classification.

Therefore, it would be easiest to classify the plants by their method of reproduction.

Far Part A of my experiment, I will use:
- A bryophyte: A non-vascular plant
- A tracheophyte: A vascular plant

For Part B of my experiment, I will use:
- An angiosperm: A class of seed plants, having seeds enclosed in an ovary, and flowering - vascular
- A gymnosperm: A plant, such as a cycad or conifer, whose seeds are not enclosed within an ovary; not flowering - vascular

And maybe:
- A fungus (if I can manage to grow one somehow): An organism of the kingdom Fungi lacking chlorophyll and feeding on organic matter - non-vascular
- A chromista (also if I can manage to grow one): An algae - non-vascular