Biology

The vividly coloured flowers of the dog's ears, which appear in September until December (2), advertise the plant to birds and bees, which flit from flower to flower as they feed on the rich nectar (7). Pollination is believed to be carried out by sunbirds (8), a group of birds with narrow, pointed, downward curving bills (9), suited to probing flowers for nectar. While light is essential for plants, excess light can be damaging. Under the bright southern African sun, the dog's ears plant has evolved a mechanism to protect itself against damaging excess light. The leaves produce wax that reduces absorption by up to 50 percent, by increasing the reflective properties of the leaves (10). The wax produced by the leaf also helps prevent uncontrollable water loss (11), an important measure for plants growing in warm, dry conditions. Dog's ears plants also have properties which make them valued by humans. The succulent leaves of the dog's ears are used medicinally, for the treatment of warts and abscesses (8), and when heated, the leaves form a substance used to treat boils and inflammations, particularly earache (7). Surprisingly however, animals that graze on this seemingly innocent plant may suffer from cramps, resulting occasionally in death (5).