Common name: Large Bellflower
Scientific name:Wahlenbergia Linifolia
IUCN status: Critically endangered
Natural History
There were once four species of bellflowers endemic to St Helena. Two of these are now extinct. Of the two that remain, the large bellflower is critcally endangered of becoming extinct. Only the small bellflower has managed to maintain good numbers in many different sites around the island.
The large bellflower has become increasingly rare as its natural habitat, the tree fern thicket, has declined in area and become heavily invaded with alien plant species. The large bellflower once grew commonly amongst the tree ferns of the Peaks. In the mid 1800s Mellis records the large bellflower as being quite common on the Sandy Bay side of the ridges. Mellis even commented on how well the white flowers of the bellflower contrasted with the red flowers of the fuchsia, a species which had escaped from peoples gardens after being introduced to the island. Today, the large bellflower has been lost from the tree fern thicket of the central ridge, now Diana's Peak National Park, where about 100 years ago it was still quite common. Instead of large bellflowers growing out from the trunks of the tree ferns and cabbage trees , the fuchsia grows in great profusion and has become a serious weed on the Peaks.
DESCRIPTION
The large bellflower has a spreading habit and can reach a height of about 50 cm. It has a long narrow leaves of up to 50 mm in length that are slightly serrated. The flowers are bell-shaped and white and about 20 mm in diameter. Flowering occurs all year round with the main flowering period in the months of July and August.
NUMBER OF SURVIVING POPULATIONS
Today, the large bellflower can only be found at High Peak. Three small populations are known which are all rather inaccessible. The bellflowers naturally grow out of the live trunks of tree ferns and cabbage trees, but are also found growing on exposed cliff sites.
CONSERVATION RECOVERY PROGRAMMES
The Enviromental Conservation Section has begun a study of the flower structure and mating system of the large bellflower. The Section has four cuttings growing at the nursery which have been taking from plants in the wild. These cuttings, which are flowering are being used to make observations about the biology of the flowers so that seed set can be manipulated by manual cross pollination. This will be important for plants which will be grown in a seed orchard that is in 'captivity'.
Using these four plants plus additional cuttings and seedlings the section intends to set up a seed orchard, in a shade house at the nursery, for the large bellflower. The seed orchard will be used to provideseed and seedlings to restock the populations at High Peak and at some time in the near future reintroduce the bellflower to Diana's Peak National Park.