The Cactus Patch
Volume 12       November 2009      Number 11

What Is A Caudiciform?
by Sidney Kelley

A caudiciform is a plant with a swollen, water-storing stem or root/stem combination called a caudex. A caudex is a type of thickened stem that is either underground or near ground level. It may be swollen for the purpose of water storage, especially in xerophytes.

Caudiciforms are an unscientific collection, crossing divisions, orders and families. There are over 100 genera of plants that have species that can at least loosely be described as caudiciforms.

The swollen root or stem is used for water or food storage, allowing the plant long periods of survival without water or other forms of nutrition. Not all caudiciforms fit easily into the category of cactus and succulents, but most do.

Caudiciform plants, or Fat Plants, are water-retaining plants adapted to arid climates or soil conditions. Many species from different plant families have developed this form of storing water rather than in foliage or in fat leafless stems. These plants produce green leaves and shoots during periods that are favorable for growth, and live off water and food stored in the caudex during long dry spells. Some of the plants lose their branches and vines, when they dry out, leaving Only the caudex and the bigger roots. This reduces evaporation.

Some of them are dioecious, which means there are different male and female plants. Others are monoecious; both male-and female flowers on the same plant. Unfortunately, that doesn't necessarily mean they can self-pollinate. Luckily, it is possible to make cuttings of many of them, but the cuttings don't necessarily form a caudex.

In habitat some caudexes lay deep down in the ground, protected from extreme weather conditions and animals. Some of these won't stand to be exposed, and don't seem so interesting. Others are partly exposed, and some are fully exposed. That can be a result of habitat such as in bare rocks with small cracks, leaving no room for a caudex. Collectors that are interested in showing the ones with the underground caudex or root system gradually raise the plant each time itís repotted to reveal it.

Why grow Caudiciforms?

These are sometimes plants that one needs to develop a taste for as not all are attractive or even all that interesting looking, at least not until you get to know them better. They really are fascinating and curious plants. And some are exceptionally attractive specimens.

How does one take care of a Caudiciform?

There is no simple answer to this question. Since there are many examples of caudiciforms in many different and completely unrelated plant families saying anything in general terms about them is difficult. In general, it is best to err on the side of less water than more if you are unsure. Almost all do best in very well draining soil (some have to be so well draining that the soils are nearly pure rock, sand or pumice, or else the plants will rot). And most prefer warmth over cold (again, not always true).

These plants are wonderful curiosities and are very popular among those plant collectors and growers that like odd or peculiar plants.

Paul Bowle's Adenium obesum

Ed Colley's Pachypodium namaquanum

Jack Kelley's Ficus palmeri

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