Devil's Claw

Devil's Claw, Proboscidea louisana, should not be confused with Harpagophytum procumbens although the flowers and pods of both plants have some resemblance to each other. The latter, while also commonly called Devil's claw, originated from Africa, has tuberous roots, and is attributed to being beneficial in treating various diseases and commonly sold in pill form as "Devil's Claw".

Devil's Claw, Proboscidea louisianica (Martynia louisiana), comes from the Martyniaceae family. Common names of the genus include devil's claw, pale devil's claw, unicorn plant, devil's horn, ram's horn, and aphid trap. Some species are perennial and arise from a tuberous root, while others, such as louisianica, are annuals.

The ripe Devil's claw pod splits into two parts.

The Plant

The plant starts out attempting to grow upright. If it is growing in poor conditions, it may be a spindly plant only a foot tall, little if any branching, and few pods which are small. However, the seed is viable and can germinate the following year.

Given better conditions, the plant can become quite large. This is one multibranched plant that has sprawled across the ground.

Notice the first group of pods are starting to ripen as the plant continues to bloom and set more pods.

Having a touch sensitive stigma appears to be limited to the order of Scrophulariales. The Martyniaceae family is one of at least four families of the order which has this attribute.

The end of the stigma is split into two flaps. Once they are touched, they quickly close within seconds.

When an insect carrying pollen lands on the flower, it touches the stigma flaps, depositing any pollen received from other plant's flowers. The flaps close, preventing any self pollination when the insect (or hummingbird) exits with that flower's pollen.

The insect picks up new pollen from the anthers just under the stigma and carries it to another flower. While the insect may visit the same plant, at least the mechanism reduces part of the potential of self pollination.

After the flower falls, the stigma is easily seen with its two flaps. The pod soon starts developing. It is covered with glandular sticky hairs as are the flowers, and the rest of the plant.

Some have observed that some carnivorous plants have sticky hairs and since Devil's Claws and related plants have sticky hairs, then they must be carnivorous plants or on their evolutionary track to be come one. However, some have tested them and found no evidence of digestive enzymes. It is just a sticky plant.

There are several different types of sticky plants which are not considered carnivorous, so why should Devil's Claws be considered so? One may then ask, why are they sticky? A most obvious reason would be for the plant's protection.

One may notice many dead insects trapped in the sticky hairs. However, there are some insects which do not seem to mind the sticky hairs of Devil's claws and other sticky plants. They seem to do well with little competition. Some species of Hemipteran, or true bugs, are some that frequent the plants. These insects, which look like giant mosquitoes and do have piercing mouth parts, only suck the plant's juices. These slow movers do not seem to be trapped in the sticky hairs. Tomato hornworms are another insect which do not seem to mind the sticky hairs. However, they do appear to prefer tomatoes to devil's claw, so although you can plant a "trap crop" of tomatoes for your devil's claw, the other way around doesn't work well. And, tomatoes don't trap the hornworms 100% as some have been found on devil's claws alongside of tomato plants.