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Plant Highlight: Kleinia anteuphorbium var. anteuphorbium (Senecio anteuphorbium)
by Brian Kemble
Taxonomic placement
The Asteraceae, or Daisy Family, is one of the largest families of plants, and it has its share of challenges when it comes to determining what is related to what, and how closely. One such problem centers on the many plants that have been placed in the genus Senecio, which grew to be one of the largest genera of all the flowering plants. In recent years, much work has been done examining the DNA of the various species to try to logically group them into smaller and more cohesive genera, based on their presumed ancestry. Many of the succulent species are now put into the genus Kleinia (first published in 1754, with the species assigned to it sometimes being put into Senecio and sometimes separated out) or into the newly created genus Curio (published in 1997). For the most part, these two genera encompass the succulent plants formerly included in Senecio, with the following traits separating them from each other: the species in Kleinia are primarily stem succulents (though some have succulent leaves as well), and they usually have a dormant season when they lose their leaves. In contrast, the species in Curio are primarily leaf succulents (though they may have succulent stems as well), and they are evergreen. In addition, the flower heads in Kleinia tend to be larger, and they are often colorful, while those in Curio tend to be smaller and white to off-white. In many Kleinia species, there are conspicuous lines on the stems, radiating out from below the leaf attachment point, and then bending downward and extending down the stem as parallel lines.
Area of occurrence
Although the genus Kleinia extends as far east as Southeast Asia, the majority of the species are found in Africa, with the greatest concentration at the southern end of the continent. At the northwestern end of the range is a species native to the Canary Islands, and nearby along the arid southwestern coast of Morocco is Kleinia anteuphorbium var. anteuphorbium (Senecio anteuphorbium). The name “anteuphorbium” was applied to the plant because of an old belief that its sap was an antidote to the poisonous milky sap of many Euphorbia species, but there is no evidence in support of this.
About the plant
In its dry native habitat, Kleinia anteuphorbium var. anteuphorbium is leafless for a large part of the year, with its growing period coming during the winter months, since this area has a Mediterranean climate. It is usually found growing in open sunny positions, with its ascending cylindrical stems crowded together and forming a small shrub, typically 40 inches (1 meter) or less in diameter, but occasionally double this. Mature plants range from about 40 inches to 100 inches in height (1 to 2.5 m). The stems are usually cylindrical, though occasionally they may be slightly laterally compressed so that they are oval in cross-section, and they have a thickness of .4 to .6 inch (10 to 15mm), or sometimes even more than this. They are pale green in color, with a waxy coating that makes them look whitewashed. There are 3 narrow lines emanating from below the leaf attachments; these are dark green and stand out against the pallid stems, giving them a pin-striped look. The smooth green succulent leaves are up to 1.6 inches long (4 cm) and bend upward so that they rise alongside the stem. The upper leaf surface is convex, with edges that are slightly rolled under, resulting in a lower surface that is shallowly channeled. The leaves have a thickness of about .08 inch (2 mm). The stems branch mostly from the base, but occasionally higher up as well.
About the flowers
This is a fall-flowering species, but the flower heads are not especially showy, and its popularity in cultivation comes mainly from its vegetative characters. In the Asteraceae, clusters of small flowers are grouped in a cup called a capitulum, and the bracts (modified scale-like leaves) on the outside of the capitulum are called phyllaries. While the phyllaries in some daisies may be spreading and stick out at various angles, those of K. anteuphorbium ascend vertically alongside each other, ringing the base of the flower cluster like a picket fence. Though green if grown in some shade, the phyllaries are often tinged with purple or reddish purple when grown in full sun. The tight group of small white flowers bursts forth from the cup formed by the phyllaries, with yellow pollen visible on the tips of the protruding stamens. The flower heads are about .8 inch in diameter (2 cm), and they have a sweet fragrance. The flower heads emerge at the tips of the stems, sometimes with just one capitulum and sometimes with several. After pollination, the flowers develop small black oval seeds. Although these are not difficult to germinate, plants are usually grown from cuttings, which root readily.
Closest relative
It should be noted that Kleinia anteuphorbium var. anteuphorbium has a close relative from northeastern Africa and the Arabian Peninsula. This was originally named as a separate species, Kleinia odora (Senecio odorus), but it is now treated as a variety of Kleinia anteuphorbium, Kleinia anteuphorbium var. odora. With this placement, the original variety from Morocco becomes Kleinia anteuphorbium var. anteuphorbium, though it is often seen labeled simply Kleinia anteuphorbium. The var. odora differs in that it tends to branch more and has longer leaves (up to 2.2 inches, or 5.5 cm). The flower heads also have fewer phyllaries (generally 10 or fewer, vs. more than 10 in var. anteuphorbium), with the number of flowers in the capitulum also being lower (6 to 25 in var. odora vs. 30 to 50 in var. anteuphorbium).
Plants in cultivation
In cultivation, K. anteuphorbium is easy to grow if given excellent drainage and plenty of sun. Lower light levels result in stems that are floppier and not as tightly bunched. In Mediterranean climates, it can be grown in gardens without supplemental water, but occasional watering will allow it to retain leaves for much of the year. Although it can withstand overnight lows a few degrees below freezing, it is not hardy enough to withstand sustained freezes. Stems can be severed and left to callus before inserting them in soil to root them, making this species easy to propagate.
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