January 2005 Plant Highlight: Senecio articulatus

by Brian Kemble

 

Image of Senecio articulatus   Image of S. articulatus flower  

Senecio articulatus is a member of the daisy family, or Asteraceae (formerly known as the Compositae). This family has a distinctive type of flower, in that what appears to be a single flower is in fact a group of many small flowers (florets) surrounded by a cup-like wrapper known as an involucre. Such a compound flower is called a capitulum. In some cases (as with S. articulatus) this bouquet of florets is the whole story, but in others (as with marguerites and many other familiar daisies) the single-flower illusion is enhanced by having a ring of modified florets arranged around the outside of the cluster. These outer florets are stretched out on one side to look like the petal of a normal flower. Such outer asymmetrical florets are termed “ray florets,” while the symmetrical ones within are “disc florets.” Some species of Senecio possess ray florets, while others such as S. articulatus lack them.

The genus Senecio is a large one, with well over a thousand species occurring worldwide. South Africa has an especially diverse assortment of species, including many of the succulent ones. S. articulatus is one of these, coming from the southwestern part of the country. Rainfall in its habitat may come in summer or winter, but our plant at the Ruth Bancroft Garden shows a definite preference for winter growth. Although more often seen as a potted plant, it has performed well for us in the garden and proved able to survive mild bouts of freezing temperatures.

S. articulatus has fat cylindrical stems with periodic constrictions, giving an impression of sausage-links. These are decoratively enhanced by reddish-purple markings. The notched and dissected leaves are a bright green, sometimes flushed with purple. It is the stems and leaves which account for much of the plant’s popularity, since the flowers are not showy. The florets are white or yellowish-white, but without ray florets they don’t stand out. Seen close-up, however, they are not without appeal.

Image of S. articulatus stems
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