The science bit
Tree up to 10m tall. Bark thick and grey. Branchlets stout, appearing cylindrical (terete), densely hairy (pubescent). Leaves up to 15cm long, lanceolate, covered in slightly flattened silvery hairs. Each plant has either male or female flowers (dioecious). Male collections of flowers (inflorescences) spherical, contained in a ring of small leaves; female inflorescences contained within a ring of broader, rounder leaves; both covered with layer of fine, minute silvery hairs. Fruiting cones silvery, up to 9cm long, retained for several years.
- This plant is called the silver tree because on a sunny day it glistens with a stunning silvery sheen.
- To reduce water loss the hairs flatten and not only reflect away a lot of heat and light but also reduce the level of transpiration to prevent the leaves from drying out. This means that the tree looks more silvery on hot sunny days than rainy days.
Where it grows
It grows on cool, eastern and southern slopes on granite-derived clay soils around Kirstenbosch in South Africa. Eight wild populations of these plants are only found within 11km of this area of fynbos. Fynbos is Afrikaans for ‘fine bush’, which refers to the evergreen, fire-prone shrubs that live in the nutrient poor soil. This area of South Africa has one of the greatest varieties of plants on Earth and is botanically richer than the rainforest.
This plant is classed by the International Union for Conservation of Nature as ‘rare’ and 'vulnerable' as the populations are small and only grow in a limited area.
Its current threats include the expansion of cities, towns and villages; the splitting up of silver tree populations; and competition for resources by invasive alien plants. Furthermore, its fynbos habitat is changing: the fires that once were crucial to the tree's survival are now being more efficiently controlled by people. This has led to forests springing up, where silver trees find it difficult to compete with coniferous trees. Squirrels are also proving to be problematic.
In its natural habitat in South Africa, the silver tree is mainly pollinated by beetles attracted to the flowers, which are said to smell like root beer.
- Lanceolate: narrowly ovate and tapering to a point.
- Transpiration: the process by which a plant evaporates water from its leaves and gets water from the soil.