The Golden Torch cactus (Echinopsis spachiana) is native to South America (Argentina and
Bolivia) and is classified as a Category 1 invasive alien plant in South Africa
(Conservation of
Agricultural Resources Act, 1983 (Act No 43 of 1983) (CARA)). Category 1 plants are declared weeds and may
not be planted or propagated. Trade of the
seeds, cuttings or other plant material used to propagate these plants are
prohibited. They may not be transported or be allowed to disperse. Although South Africa hosts a large diversity
of succulent plants, species of the family Cactaceae (spiny succulents) are not
native to South Africa (geen kaktus plante is inheems tot Suid-Afrika nie). The only time this plant is appealing to the
eye (according to me) is when it blooms; it produces large and beautiful white flowers.
There are several small patches where the Golden
Torch cactus (Orrelkaktus in mooi Afrikaans) has become naturalized in the veldt
around De Rust. These plants started
flowering in late November 2011 and are still continuing to flower. The plants flower in bursts and our neighbour
believes that when they flower it is a sign that it is going to rain. The big and showy flowers have a noticeably
strong sweet sent and only lasts for a few days.
Where this cactus is native it could be
pollinated by either bats, hummingbirds, moths or bees – common pollinating
agents of other cactus species. The
flowers of the Golden Torch cactus is nocturnal (flowering during the evening)
just like many other cactus species. I’ve
done a literature search on the pollination of the Golden Torch cactus but did
not find any scientific papers on the subject.
 |
| Photo from: http://www.learner.org/jnorth/tm/spring/Bats_PollenProtein.html A bat visiting the flower of a different cactus species. |
Here in the Klein Karoo, honeybees visit the
flowers and particularly collect pollen from the stamens, for their pollen
baskets are loaded with pollen.
 |
| The style is the thicker protrusion in the middle of the flower, splitting up into many ends. There are numerous stamens from which the honeybees collect the pollen. |
It is not clear whether honeybees would be
agents in the spread of this alien invasive weed by pollinating the flowers,
unless their pollen dusted bodies come in contact with the stigmas of the
flowers.
No
biological control agent has been released in South Africa for this invasive
weed species. The plants are apparently
sensitive to frost.
