Asteraceae (formerly Compositae) - Daisies, Sunflowers
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The Asteraceae is the second largest family of flowering plants (Division Magnoliophyta) with at least 1100 genera and over 20,000 species included. The type genus is Aster, typified by daisies and sunflowers with star-shaped flower-heads. The Asteraceae
includes shrubs and a few trees.
Many Asteraceae are cultivated for their flowers. Sunflowers (upper right) are cultivated for their oil-rich seeds. Tussilago farfara (Coltsfoot) (lower right) is a traditional medicinal plant used as a cough suppressant. The natural insecticide Pyrethrum, made from the dried flowers of Chrysanthemum (Tanacetum) cinerariifolium and C. coccineum, has been in use in Persia since 400 BC and in Europe for over 200 years. Pyrethrum and analogues are now made by organic synthesis.
However only a small number of genera in the Asteraceae, including Kleinia, Notonia, Othonna, and Senecio, have succulent members. Most succulent species are leaf succulents although there are some stem succulents and caudiciforms. The inflorescence of all Asteraceae characteristically consists of tiny bisexual tube-like flowers tightly packed into heads known as a capitulum. Very often, a marginal ring of larger petals surrounds the flower head with each marginal floret (usually female) contributing a ray petal. Some species have discoid flowers without the marginal florets.
Senecio includes the Ragworts, many species of which contain Pyrrolizidine alkaloids and other toxins, known to cause liver damage and hemmoraging of livestock. The same alkaloids are incorporated into caterpillars of butterfly species that use Ragworts as food plants and confer a degree of protection against predation. Not only do the caterpillars and butterflies taste distasteful to birds but subsequent nausea from the alkaloids "trains" the bird to avoid this species.
Cultivation: Many species of Asteraceae are relatively undemanding in cultivation, although Othonna includes some tricky caudiciforms that should be watered sparingly. The white farinose coating on Senecio haworthii is removed by the slightest touch or even a few drops of water. It is a challenge to grow a perfect specimen; watering should always be from the base of the pot. Trailing members of Senecio grow well in hanging pots from which the trailing stems hang down.
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| Kleinia abyssinica |
Senecio barbetonicus |
Senecio citriformis |
Senecio galpinii |
| Senecio haworthii |
Senecio junceus |
Senecio medleywoodii |
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Plant Families with Succulent Species 
