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 Mediterranean basin. Under those hedges and adjacent areas soil physical properties, nitrogen and organic matter are considerably improved. Structural stability of the soil is enhanced, runoff and erosion are reduced, while water storage capacity and permeability is enhanced. Prickly pear plantations also have a positive impact on plant growth of other species by improving severe environmental conditions which facilitate colonization and development of herbaceous species. Opuntia ficus-indica is being advantageously used in Tunisia and Algeria to slow and direct sand movement and enhance the restoration of vegetative cover, minimizing deterioration of built terraces with its deep and strong rooting