They are known as new world plants because the roughly two thousand documented species, with one exception, are indigenous to North, Central and South America.

Most people think desert plant when they think cactus. They are a group of succulent plants with spines on their stems, and they thrive in arid regions.

Different types of cactus are used for landscaping throughout the desert southwest, and cactus flowers often figure into the planting decision process.

When botanists think cacti, they also think flower, albeit in a different manner. Botanists think of cactus flowers as sharing a similar anatomical makeup based on four factors.

First, Cactus flowers generally do not show a clear differentiation between the petals and sepals (the green leaf like parts under the petals). The side view of the cholla flower in the top picture, for example, does not show green, or any other color, sepals at the bottom of the petals.

The second and third factors are the presence of multiple stamen and stigmas, the reproductive parts of the flower.

The final factor defining a cactus flower is the presence of an inferior ovary. The ovary is situated below the petals and sepals, and not shown in the picture.

Click on any link in the box to see more cactus pictures.

© 2007-2008 Patricia A. Michaels