Type 2 - Barrel Cactus. Single fat stem that is globular or columnar.

Barrel cactus are some of the most eye-catching plants because of the unusual size and shape. They don't look like any other plants in there habitat, with their fat round bodies; and they can become quite large. Barrel cactus take on a globular shape when young, which could be more than 30 years. Then, most will become columnar. It is possible to have a barrel cactus that is two feet wide by seven feet tall.

Two of the most popular genera of barrel cactus are Echinocactus and Ferocactus. Most people have heard of the Golden Barrel cactus (Echinocactus grusonii), which can grow to be 24 inches wide the 36 inches tall. However, there is Echinocactus platycanthus, which can mature at 30 inches wide and 84 inches tall. We have all heard of the Fish Hook cactus (Ferocactus wislizeni). But what about Ferocactus diguetii that can reach up to 12 feet tall (3.6 m), 3 feet in diameter (90 cm).

As with hedgehogs there are also contrasts in size with barrel cactus. Some of the smaller ones are Echinocactus texensis, E. horizonthalonius, Ferocactus latispinus, and F. viridescens.

Many the South American cactus species also form a barrel shape, such as Gymnocalycium saglionis, Notocactus herteri, and Echinopsis bruchii (Soehrensia bruchii).

Echinocactus platyacanthus	Ferocactus pilosus	F. cylindraeceus	F. latispinus