- Hedera helix, the common ivy, European ivy, or just ivy, is a species of flowering plant in the family Araliaceae. It is native to most of Europe and parts of western Asia. Ivy is a clinging evergreen vine that grows on tree trunks, walls, and fences in gardens, waste spaces, and wild habitats. Ivy is popular as an ornamental plant, but escaped plants have become naturalised outside its native range. Ivy has considerable cultural significance and symbolism.
- Siliceous rock (Wikipedia)
Siliceous rocks are sedimentary rocks that have silica (SiO2) as the principal constituent. The most common siliceous rock is chert; other types include diatomite. They commonly form from silica-secreting organisms such as radiolarians, diatoms, or some types of sponges.