Pseudolithos (2009)

By Eric Driskill (November 2009)

Pseudolithos are in the Asclepiadaceae family and come from Somalia, Oman and Yemen. Oman and Yemen are countries on the Arabian Peninsula in southwest Asia. Somalia is located in the Horn of Africa, east of Ethiopia. Many strange and interesting plants grow in this area. Some would say the difficulty of traveling into and out of Somalia equals the challenge of growing these fascinating plants.

The name “Pseudolithos” comes from the Greek “pseudo,” false, and “lithos,” stone. Being a rock hound, I have to say that I have yet been graced with finding stones with the character and symmetry of any of the pseudolithos.

The plants grow in a dry, tropical area, and like most of the succulent milkweeds (stapeliads), are generally pollinated by flies due to the flowers having a rotten meat bouquet. As if that wasn’t enough, the flowers are numerous, in umbels from hemispherical peduncles with motile, club-shaped hairs at the tips that “dance” with the slightest breeze. No passing fly could resist.

The half-inch flowers are a beautiful purple/maroon hue. When you’re lucky enough to have flowers pollinated, you will see two seed horns develop with 10 to 20 seeds in each pod. If you intend to collect the seeds, take care, because when the pods open, they will take flight on the first available breeze. Contain the pods in anything that will catch the seeds when the pod has matured or test your luck with visiting right when they open.

Stems are spherical and can reach sizes up to 4.5 inches tall and 4.5 inches wide. Most plants you find for sale are 1 to 2.5 inches tall and to 2.5 inches wide. Propagation is from seed. Most authors tell you seed is the only method of propagation, but when one of my plants started to rot from the bottom, I quickly cut away all soft tissue and succeeded in rooting five out of eight cuttings. As an emergency measure, you can also graft plants onto tubers of Ceropegia woodii, C. linearis or certain Carallumas species.

Pseudolithos are not the easiest plants to grow, but at the same time are not impossible. I would suggest leaning toward brighter light and a fast-draining soil. You may need to water more frequently with this soil, but your plant won’t have wet feet for long periods of time either.

When underwatered, plants deflate and become misshapen from their usual spherical appearance. When overwatered, the plants deflate to an expensive mush in record time. With that said, I think most people underwater for fear of rot. You may also want to underpot the plants, as well.

Once you have tested and fine-tuned your horticultural skills with less-expensive stapeliads, you should consider adding a pseudolithos to your collection. Most likely, you will first find P. migiurtinus for sale. When you succeed with that species, I would suggest you then consider adding a P. caputviperae or P. cubiformis to your collection.