Plant Highlight: Orbea variegata
By Brian Kemble
The succulents known as stapeliads belong to the Tribe Stapeliae within the Apocynaceae, or Dogbane Family. They were formerly placed in the Asclepiadaceae, or Milkweed Family, but this whole family was merged into the Apocynaceae; under the new classification the milkweeds are treated as the subfamily Asclepiadoideae within the larger Apocynaceae. The subfamily Asclepiadoideae includes many succulents, including plants with swollen tuberous bases (Brachystelma species), plants with thickened succulent leaves (Hoya species), and plants with succulent stems. All of the stapeliads are in the latter category, and they typically grow as clusters of cylindrical stems with vertical rows of toothy projections along their sides. They are well known for their remarkable five-pointed flowers, and these are often referred to as “carrion flowers” because many of them employ foul odors to attract the flies that pollinate them. Orbea variegata, native to South Africa, is an example.
Orbea variegata is a common species along the coast in the southwestern part of South Africa, and it was brought to Europe soon after the Dutch founded their settlement at Cape Town in the mid-1600’s. However, the classification of the stapeliads has undergone many changes, and for a long time the species was known under the name Stapelia variegata, so it may be found under this name in many books and plant collections.
About the Plant
In time, Orbea variegata becomes a mat of many sprawling stems that can reach a diameter of 20 inches (50 cm) or more. The stems can be up to 10 inches (25 cm) long, but because they recline, the height of the plant is usually only about 4 inches (10 cm). Each stem is smooth, green with purple blotches, and about .4 to .6 inch in diameter (1 to 1.5 cm), with four sides. The ridges between the sides have a series of toothy projections, or tubercles, that give the plant an almost spiny appearance. Although the new stems mostly come from sprouts at the base of the plant, older stems may occasionally branch by dividing at the tip.
About the Flowers
Flowering in Orbea variegata occurs mostly in late summer and fall. The flowers are held on a short stalk (peduncle) emerging from near the base of a stem, with one to three flowers arising from the peduncle. The pedicels (stalks of the individual flowers) are up to 2⅓ inches long (6 cm), and they arch outward so that the buds (and the flowers that follow) are resting on the ground facing upward. The open flowers are 1.8 to 3.15 inches in diameter (4.5 to 8 cm), with their five ponted lobes and rough texture reminiscent of a starfish. The face of the flower is cream, pale yellow, or greenish-yellow with markings that are dark red or maroon. At the bases of the lobes is a thickened ring called an annulus, and this has the same color scheme, but with finer maroon spots and more yellow. At the very center is the five-pointed corona, like a star within the star, and this is where the reproductive parts of the flower are located. Many stapeliads have flowers that emit a foul odor in order to attract the flies that pollinate them; this is true of Orbea variegata, though its smell is not as strong as that of some other species.
About the Fruit
A successfully pollinated flower develops a pair of more or less erect cylindrical follicles containing the seeds. The follicles are dark green mottled with pale green (tapering to a blunt point) and they are about 5 inches long (12.5 cm). At maturity, they dry and split open to release the many small seeds, each with a tuft of silky hairs that allows them to be carried aloft by the wind.
Care and Maintenance
Orbea variegata is not difficult to grow. It comes from the part of South Africa where the rainfall is mostly in winter, so it does well in other Mediterrnean climates (such as that of the milder parts of California). Where winters are cold, it can be grown indoors in a pot, with plenty of sun, excellent drainage, regular watering during the winter, and occasional water in summer.
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