Pteris

The fern Pteris vittata germinates in walls, on rocks and on roots exposed at the base of trees.. This one came up among some sporelings of stagshorn fern. It is widespread in warmer climates of the world and has achieved fame because of its ability to remove arsenic from the soil. Although listed as a rare and endangered fern in NSW, this may be because of its requirement for high levels of calcium, so that it grows well in the mortar of old walls.