Of Twists & Turns: What are crested plants?

Why do plants crest?

To understand cresting, also called fasciation, one must first understand the basics of how a plant grows. Plants consist of a variety of different tissues, and these perform several different functions. Meristematic tissue is what causes active growth in plants. This tissue contains cells that are able to divide, and form new tissues, much like stem cells in humans. Meristems are present at the tips of roots, stems and branches of plants, and are what allows the plant to grow these organs. The apical meristem, or main growing point in the stem of the plant, is responsible for the normal, vertical growth of most plants. It is focused on a single point and forces the plant to grow upwards, or the roots to grow downwards.

However, with any cell that can divide, there is always the chance that something can go wrong. In crested plant, the apical meristem, which is normally a single growing point, divides into multiple smaller points. The apical meristem then grows in a horizontal line instead of a normal vertical point. This makes the plant grow sideways instead of upwards. This horizontal growth is what results in the strange shapes and forms that we have grown to love in our crested plants.

The different crested forms 

In tall, column forming plants like the San Pedro (Trichocereus pachanoi) cactus, cresting usually manifests itself as a flattened expansion of the original plant stem. This mutation causes an almost flag-like, horizontal growing structure to replace normal, vertical growth at a certain point on the stem.

Cresting is different in smaller plants that grow closer to the ground, like the famous Mammilaria elongata (‘Brains Cactus’ in its crested form). The mutation makes the plant fold in on itself. This gives it the appearance of having an unending number of twists and turns.

Plants that have more prominent stem structures are more likely to become crested than those that don’t. The more stem there is, the more chance there is for a mutation to occur. Rosette succulents like Aloe and Haworthia grow from a base, instead of a true stem. In stark contrast to cacti, these species almost never crest. It is not just the stem of a plant that can crest, though. Most plant organs can become crested, and result in things like crested flowers. Crested flowers are most common in cacti, but other species like the abovementioned Aloe and Haworthia also sometimes have crested flowers.

Varieties of crested plants

Cresting can occur in any plant, and even most parts of a plant. Our focus is on cacti and succulents, but trees, shrubs, and even flowers can become crested. There are some plant cultivars that are cultivated to form crests. Aeonium ‘Sunburst’ is a good example, and one often sees this plant available at nurseries in this form. Even in nature, some species like the Saguaro cactus (Carnegiea gigantea) are more prone to the mutation.