Opuntia in the food web. Charles Darwin was the first to note that these cacti have thigmotactic anthers: when the anthers are touched, they curl over, depositing their pollen. This movement can be seen by gently poking the anthers of an open "Opuntia" flower. The same trait has evolved convergently in other cacti (e.g. "Lophophora"). The first introduction of prickly pears into Australia is ascribed to Governor Philip and the earliest colonists in 1788. Brought from Brazil to Sydney, prickly pear grew in Sydney, New South Wales, where they were rediscovered in a farmer's garden in 1839. They appear to have
Opuntia ficus-indica the plants are used as fodder. In these cases, the spines need to be removed from the pads to avoid damage to the animals. Mostly, this is achieved by burning the spines off the pads. "Opuntia ficus-indica" for human and animal consumption is its water content in an arid environment, containing about 85% water as a water source for wildlife. The seeds contain 3-10% of protein and 6-13% of fatty acids, mainly linoleic acid. As the fruit contains vitamin C (containing 25–30 mg per 100g), it was once used to mitigate scurvy. "Opuntia" contains selenium. The red color of the