Gomphocarpus fruticosus (Milkweed, formally: Asclepias fruticosa) Family: Apocynaceae
- A small shrub with sparse foliage.
- Adventitious roots.
- Leaves are lancelet and exude a milky latex.
- The flowers are creamy-yellow and the fruit a balloon shape covered with hairs and, when ripe, the fluffy seeds are dispersed by the wind.
- The African monarch butterfly (Danaus chrysippus) lays its eggs on the underside of the leaves. The larvae eat the leaves making the butterfly toxic to predators. The monarch is mimicked by the diadem butterfly (Hypolimnas misippus) a non-toxic species.
- These bushes rely on poisonous sap to deter browsers.
- G. fruticosus grows in open grassland.
Plicosepalus kalachariensis (Mistletoe) Family: Loranthaceae
- Hemi-parasitic plant forming a dense cluster of branches and leaves in the upper canopy of trees (predominantly Acacia spp).
- Adventitious roots bury themselves under the bark and tap the nutrients from the cambium layer.
- The olive –green leaves are leathery and elongated. The tubular, red flowers appear in profusion during winter. The fruits are eaten by birds and, when the sticky seeds are wiped off the bill, the gluey coating adheres to the bark of the tree.
- There are strong symbiotic relationships between flora and fauna with this plant:
i. Mutualism: sunbirds and butterflies enjoy the nectar whilst pollinating the flowers and frugivorous bird species disperse the seed after eating the fleshy fruit.
ii. Parasitism: this plant sucks the nutrients from the cambium layer of the host plant,
iii. Commensalism: the sticky “birdlime”, extracted from the fruit by people, is smeared on branches to catch unsuspecting birds.
- Plicosephalus plants are palatable to browsers but most of these parasites are beyond the reach of these animals.
Ansellia africana (Leopard orchid) Family: Orchidaceae
- An epiphytic plant that attaches its roots to the rough bark of a tree.
- Adventitious roots cling to the epidermis of the host tree.
- Initially the leaf forms a sheath around the stem and then flattens out forming a long, thin blade.
- The golden-yellow flowers with brown blotches are scattered down the length of the racemes and appear from June to November.
- The symbiotic relationship between orchid and host is commensalism (the orchid benefits whilst the tree remains unaffected). This plant is grown in the gardens of certain tribes as, it is believed, it will bring the inhabitants good luck.
- The Ansellia grows well out of the reach of browsers.
- A. africana is frequently found high off the ground and often forms a strong affiliation with palm trees.
- Mammals eat the leaves of the Ansellia (if within reach) throughout the year.