Some Information About Cactus

The name Cacti or Cactus has been adopted by the masses as the universal term to describe succulent plants. I have heard the term used to describe a varied range of plants from Euphorbias to Fouquierias (Ocotillo) to Agaves, Yuccas, & Aloes.
By including what are not cacti, CactiGuide.com can be a more useful guide through the process of elimination. The table below lists examples of other succulents that resemble cacti but are not. This should give beginners a good start. There are exceptions to every rule and this is so true with the features used to identify cacti. Those who happen across such an exception should prepare to do some extensive research and be patient. Some of the features that separate cacti from other genera are:
Areoles- Flowers, branches, spines sprout from these- no other plant has this feature.
Spines- Perhaps the most familiar feature of cacti, spines can vary greatly in appearance, shape, size, and color. Spines are not thorns.
Flowers- Flowers are not unique to cacti, but cacti flowers are unique. Cacti flowers are typically quite spectacular and very complex. Unfortunately this field mark is only helpful, of course, if the plant happens to be blooming.
Leaves- Most cacti do not have leaves, however, some do. Pay special attention to the presence or absence of leaves.
Origin- All cacti are native to the Americas and surrounding islands. With one exception -Rhipsalis baccifera. Although, world wide cultivation has made this less helpful for identification.
Areoles- Flowers, branches, spines sprout from these- no other plant has this feature.
Spines- Perhaps the most familiar feature of cacti, spines can vary greatly in appearance, shape, size, and color. Spines are not thorns.
Flowers- Flowers are not unique to cacti, but cacti flowers are unique. Cacti flowers are typically quite spectacular and very complex. Unfortunately this field mark is only helpful, of course, if the plant happens to be blooming.
Leaves- Most cacti do not have leaves, however, some do. Pay special attention to the presence or absence of leaves.
Origin- All cacti are native to the Americas and surrounding islands. With one exception -Rhipsalis baccifera. Although, world wide cultivation has made this less helpful for identification.