Introduction

Opuntia and related species (opuntiads) are unique cacti with unusual shapes and beautiful flowers. Common in parts of the United States and Mexico; they also occur throughout most of the Americas. There are over 100 species in the United States and many more in Mexico. Opuntia Web describes opuntias of the United States. Cholla Web is our sister Website, and  it describes other opuntiads of the USA.

The Details

Opuntia macrocentra

Opuntia macrocentra

Of the many opuntias in the United States, some have been forgotten by time because botanists discovered them over 100 years ago. Some opuntias look superficially alike and only close inspection can tell them apart. Thus, casual observation might indicate one species where there are actually two. Early botanists identified them and understood their uniqueness, and we use those historical records along with field studies to identify them, their differences, and their similarities.  Moreover, there are still undescribed species and we will add them to the Website as they are known.

What We Do

Opuntia aciculata

Opuntia aciculata, new branch nestled among long glochids

We describe the various species, and we provide multiple photographs so you can see details. We try to take photos in habitat so that you can see how the plants grow and what they look like in different seasons. The goal is to describe them in easy-to-understand terms. A group of editors verifies all the information in this Website, and we strive to present accurate information. We traveled to many places to photograph many Opuntia species, and we visited many libraries to find relevant printed information. But we are  always happy to learn new things. Maybe you have new information or spotted an error or a typo. If you find an Opuntia, maybe we can help you identify it. Just write to us.

Why We Do It

Opuntia curvospina

Opuntia curovspina, north of Kingman, AZ

Opuntias are unique and worth studying. This Website helps you understand and enjoy this group of easy-to-grow cacti. One reason we study them is that they are so numerous in the warmer parts of the county, a species even grows into Canada. Also, we study them because they are so confusing in the literature and on the Web. It is a fun detective story to find the original publications and match them with the plants. Opuntia make wonderful garden plants if you match the right ones with your climate. Through mostly desert species, there are species that will grow in the southeast, the northeast, and the upper Midwest. Many Opuntia grow in climates without  strong freezes, but some fly through winters of exceptional cold. We like to grow Opuntia and writing about them helps others understand the species and decide what to grow.