Plants include all organisms found within the taxonomic kingdom Plantae, which produce their food by photosynthesis. Kingdom Plantae is further organized into taxonomic divisions, with a major separation being whether or not the plant has a vascular system. The vascular system transports water and plant nutrients via vascular tissues throughout the plant. Non vascular plants include plants such as algae, fungi, liverworts and mosses. Vascular plants are members of the subkingdom Tracheobionta.  These include ferns, club mosses, angiosperms (flowering plants) and gymnosperms(non-flowering plants).

Vascular Plants

• Angiosperms (Magnoliophyta)
  Angiosperms reproduce by flowers, which are modified shoots that surround immature seeds inside.
  
  
• Ferns and Fern Allies (Pteridophyta) Ferns are nonflowering plants that reproduce by spores, which are produced on the underside of the green leafy structures called fronds. Fern allies are similar to ferns in that they also reproduces by spores, but differ from true ferns in that they do not have the same leaf structure.
  
  
• Gymnosperms (Coniferophyta)
  Gymnosperms are nonflowering plants that reproduce by seeds that are enclosed in cones. Some of the largest and longest living organisims in the world are cone-bearing gymnosperms such as pines, firs and redwoods.

Nonvascular Plants

• Algae
  Algae and photosynthetic microorganisms are ecologically important, especially considering they make up half of the photosynthetic production of global organic matter. The microflaura are important food sources, but when there is a high concentration of nitrogen or phosphorous they can cause the water body to become eutrophic. This can lead to low levels of oxygen that are harmful to fish.
  
  
• Fungi and Lichens
  Fungi function as an extensive network of threads existing in organic matter. They secrete enzymes that decompose organic material, which results in a recycling of materials that other organisms can use. Lichens are symbiotic organisms that are a combination of a green algae or cyanobacteria and filamentous fungi.
  
  
• Liverworts and Mosses (Bryophyta)
  These are primitive photosynthetic plants that reproduce by means of spores instead of seeds.  They are often found growing on rocks and trees, with the ability to absorb nutrients directly into their leaves and stems.

With a diversity of ecosystems ranging from the deserts to the mountains, the Southwest is home to a tremendous variety of plant species, including cacti, sagebrush, grasses, and deciduous and coniferous trees.