The Cactus Patch
THE NEWSLETTER OF THE BAKERSFIELD CACTUS & SUCCULENT SOCIETY
Volume 6       March 2003      Number 3

Monstrose and Crested Succulents
by L. M. Moe

To understand what causes monstrose and crested succulents, a brief look at how plants grow is necessary. All plants grow in length by increasing the number of cells at the tips of shoots and roots. These regions of active cell division are called apical meristems and this growth is called primary growth. Some plants, most notably the monocots (grasses, lilies, aloes), have meristems (called intercalary meristems) at leaf bases that cause leaf elongation. (This is why grass leaves continue to grow after they have been mowed). In woody plants there are additional meristems called lateral meristems that produce secondary growth. The most important lateral meristem is the vascular cambium, which produces wood and bark. Monstrose and crested growth only involves primary growth.

Cell divisions in the apical and intercalary meristems are highly regulated and finely tuned in each kind of plant, resulting in distinctive stem and leaf shapes. For example, very rapid apical growth with a suppression of branching (called apical dominance) results in long, slender stems whereas, slower growth results in "fatter" stems. Stems without apical dominance are highly branched. In general, cacti have apical dominance with slow apical growth and are "fat" (and the cells filled with water, making them succulent). So, in cacti faster growth results in columnar cacti and slower growth results in barrel cacti.

Occasionally something called a growth mutation happens that "messes up" these regulated and coordinated cell divisions in the primary meristems. The causes of these mutations range from injury to bacterial or viral diseases. The three most common types of growth mutation are crests, monstrose growth and variegation.

In crests the growth mutation changes the shape of the apical meristem. Instead of a single growth tip the area of active cell growth becomes a line, resulting in fan-like or crested growth (see photos of crested Euphorbia resinifera and crested Trichocereus).

In monstrose growth, the local apical dominance is lost and every growth tip tries to grow as if it were the dominant point, resulting in a "knobby" or "lumpy, jumbled" growth.

Variegation can be a topic for a future newsletter, if there is interest. Please let me know.

Cresting and monstrose growth is not unique to succulent plants. Crests are found in many genera of non-succulent plants, including conifers and many common garden plants.

Crests and monstrose plants are grown the same as normal plants of the same species except that crests and monstrose plants tend to be more sensitive. This is one of the many reasons they are often grown as grafts. Monstrose and crested plants flower and produce seed just as other plants do. However the growth mutations are not generally transmitted by seed so the best way to propagate these plants is by cuttings.

More photos of crested and monstrose succulents can be found in our club library or at: www.miles2go.com/crest.htm.

If you have any comments or questions or would like to
submit a photograph or article, contact

thecactuspatch@aol.com

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