According to the Cactus and Succulent Society of America, there are more than 1,600 species of succulents. Succulents belong to a genus of plants known as Euphorbia. While all of the plants in the genus are succulents by assignment, very few have a similar appearance. If you are in doubt about whether your plant is a succulent, take a closer look for some common characteristics.
Study the leaves of the plant. If the leaves are thick and ridged, then the plant is a succulent. Succulent leaves are specialized for their desert environment in that they store water more efficiently than regular plants in their leaf tissue.
Look for thorns or spines on the plant. Succulent plants use spines and thorns as a defense mechanism against animal nesting and feeding.
Check the winter temperatures in the area of the plant. Succulents are desert plants, requiring temperatures above 20 degrees Fahrenheit.
Check the soil. If the soil is sand or clay, then it is most likely a succulent, as succulents thrive in desert sand.
Water the plant every day for a week. If the plant's leaves appear swollen at the end of the week, then it is a succulent, and the leaves are storing as much water as possible. After this step, avoid watering the plant again for at least a month.