Families of Succulent Plants

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Asteraceae (Compositae) - Daisies, Sunflowers

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.

Cultivation: Many species of Asteraceae are relatively undemanding in cultivation, although Othonna includes some tricky caudiciforms that should be watered sparingly. Trailing members of Senecio grow well in hanging pots from which the trailing stems hang down.

Sunflowers

Coltsfoot

*Dendroseris* D. Don 1832 (Cabbage Trees) All 12 species in the genus Dendroseris are endemic to the Juan Fernandez Islands, about 400 miles West of Chile. The genus is very unusual in being woody, or semi-woody trees and shrubs, and interesting rather than truly succulent. All species in the genus are rare or endangered.

*Dendroseris litoralis* Skottsberg 1922 a palmate pachycaul from the Juan Fernandex Islands West of Chile. This species came close to extinction in the 1980s when only a handful of plants remained. The large, rubbery leaves are edible and readily eaten by feral goats which contributed to the plant's demise. The leaves are said to have sustained the castaway Alexander Selkirk. The large orange flowers are hummingbird pollinated. Fortunately, the flowers are self compatible so seed is readily available and the species grows in several botanic gardens.

			*Helichrysum milfordiae*
*Helichrysum milfordiae* is a choice cushion-forming alpine growing at elevations of up to 8000 ft in the Drakensberg Mountains of South Africa. While this confers a degree of hardiness, plants should be protected from winter wet. The rosettes are markedly pubescent. The white to pinkish papery flowers are produced in Spring, persisting on the plant as shown extreme left. Several species of *Helichrysum* are grown for their "everlasting flowers" that when cut young and dried retain their shape and colour. Helichrysum augustifolium is the source of an essential oil used as a fragrance.

	*Leptonella dendyi* Syn. Cotula dendyi a vigorous, hardy perennial ground-cover plant from New Zealand where it grows in mobile scree. The slightly succulent dissected green leaves take on a bronze colour in full sun and set off the starry cream flowers. Grown hard it makes an impressive subject for an alpine garden but is liable to spread in more favourable conditions.
*Senecio* Linnaeus 1753 A large genus of around 1500 species that has been variously split into *Kleinia* and *Notonia* but is presently united. Many species are non-succulent, weedy Ragworts and Groundsels but there are sufficient undemanding succulent plants here to interest the collector and several species are worth growing for their striking, brightly coloured pom-pom flowers. Several Senecios are stem succulents with vestigal leaves. *Dendrosenecio battiscombei* Syn. Senecio battiscombei from Mt. Kenya and Mt. Kilimanjaro is noteworthy for growing up to 20 ft tall with large rosettes of leaves supported by stout, woody trunks. Many species of Senecio contain Pyrrolizidine alkaloids and other toxins, known to cause liver damage and haemorrhaging 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.

Senecio articulatus Linnaeus fil 1845 (Candle Plant)
A common cottage-windowsill plant, native to the Cape Province of South Africa.
The globose to sausage shaped jointed stems form a disorderly clump. Stems tend to fragment at the joints, but each segment will root and form a new plant. During active growth the stems bear leaves that are notched into arrow shapes along the petiole. The inflorescence is a cluster of small flowers consisting mainly of tufts of yellow stamens.

	*Senecio barbertonicus* Klatt 1896 (Succulent Bush Senecio, Barberton Coltsfoot) named for: occurrence around the South African town of Barberton A shrubby plant from South Africa, Zimbabwe and Mozambique with narrow, upward-pointing leaves clustered towards the end of green stems which become brown and woody with age and may extend to 6 ft. The leaves have a groove on their upper face. Old leaves are deciduous and leave a scar on the stem. The fragrant golden flowers around the growing point are small tufts of yellow stamens. This species grows at modest elevations and is said to tolerate mild frosts.
	*Senecio galpinii* Hooker 1892 named for: Ernest Galpin 1858-1941, South African banker, amateur botanist An upright South-African plant with lanceolate blue-green leaves which continue along the long, branched flowering stem, making a smooth transition to smaller bracts. The flowers are bright orange pom-poms with orange pollen.
	*Senecio haworthii* Schultz-Bipontinus 1873 named for: Adrian Hardy Haworth 1767 - 1803, English botanist & entomologist A classic white plant whose upward-pointing, ovate, succulent blue-green leaves are densely-covered in white farinose wax. The white coating is removed by the slightest touch or even a few drops of water. While the plant is easy enough to grow, it is a challenge to grow a perfect unmarked specimen; watering should always be from the base of the pot. Old plants lose leaves around the base. Native to the Northern Cape of South Africa.
	*Senecio herreanus* Dinter 1932 (Gooseberry plant) named for: Hans Herre 1895-1979, German botanist - similar to *S. rowleyanus* but more robust with stems one eighth of an inch in diameter, bearing globular leaves up to a half-inch in diameter with longitudinal purple-edged windows. Suitable for a hanging pot.
	*Senecio junceus* Harvey 1865 junceus = rush-like, Latin: juncus = rush a stem succulent with thin, jointed green stems up to quarter of an inch in diameter. A few vestigal leaves and the flower stems are produced near the growing stem tips. The branched inflorescence bears clusters of bright yellow flowers with four or five ray petals around the central cluster of stamens. Native to the Western Cape and Cape of Good Hope of South Africa.

	*Senecio nyikensis* Baker 1897 Syn. Senecio abyssinicus An upright plant with oval blue-green leaves, making this Senecio worth space even when not flowering. The flowers on long, branched stalks are spectacular crimson pom-poms, decorated with bright yellow pollen. Native to a wide range of Central and East tropical Africa from Nigeria to Kenya, Tanzania and Ethiopia. Although the plant is poisonous in large doses, an infusion of the tuberous powdered root is a traditional remedy to promote healing of cuts and sores and for diseases of the eyes and syphilis.
	*S. nyikensis var hildebrandtii* is a more compact plant with orange-red flowers.

	*Senecio medley-woodii* Named for: John Medley Wood 1827-1915, South African botanist an evergreen shrubby plant whose oval leaves have a farinose coating. Leaf margins may bear a few tiny teeth. Flowering stems bear small numbers of yellow flowers with a marginal ring of petals around the central stamen cluster. Native to KwaZulu-Natal.
	*Senecio citriformis* Rowley 1956. A slow-growing Senecio from Namaqualand to Namibia. The trailing and branching stems about one sixteenth of an inch in diameter bear single small, lemon-shaped glaucous-blue leaves about a quarter of an inch in diameter on short pedicels. Stems produce adventitious aerial roots that grow down where they make contact with soil. The leaves of some varieties produce a waxy farinose coating that will rub off so these should be watered from below. Flowers are white tufts with yellow stamens.
	*Senecio radicans* Linnaeus fil 1845 - similar to S. rowleyanus but smaller, hook-shaped leaves.
		*Senecio rowleyanus* Jacobsen 1968 (String of Beads, String of Pearls) Named for: Gordon Rowley, English botanist. An easily-grown Senecio from South Africa where it grows along the ground under scrubby bushes. The trailing and branching stems about one sixteenth of an inch in diameter bear single small, spherical, bright green leaves about a quarter of an inch in diameter on short pedicels. Each leaf has a narrow clear window from stem to tip. Stems produce adventitious aerial roots that grow down where they make contact with soil. Flowers produced on side shoots in the winter, are white tufts with purple stamens and a spicy perfume. Grows well in a hanging basket. Variegated cultivars are sometimes available.

Left: Senecio stapeliiformis Phillips 1921 Syn. Kleinia stapeliiformis (Pickle Plant)
A stem succulent spreading via rhyzomes. The dark green angular stem has purple markings, pronounced and brittle joints where growth has ceased for a while. Vestigal leaves along the stem angles near to the growing point dry out quicly but are retained as scales. The scarlet pom-poms of many small flowers with yellow stamens are very decorative. Native to Kenya and Tanzania.

Right: S. stapeliiformis ssp. minor Rowley 1955 Syn. S. gregorii
A variety from Kenya and Tanzania with a much smaller flower and few vestigal leaves along the stems. Cristate forms are in cultivation.