Bark (botany) rope, used for example in the rigging of Viking age longships. Among the commercial products made from bark are cork, cinnamon, quinine (from the bark of Cinchona) and aspirin (from the bark of willow trees). The bark of some trees notably oak ("Quercus robur") is a source of tannic acid, which is used in tanning. Bark chips generated as a by-product of lumber production are often used in bark mulch in western North America. Bark is important to the horticultural industry since in shredded form it is used for plants that do not thrive in ordinary soil, such as epiphytes.
Fluoroacetic acid Fluoroacetic acid Fluoroacetic acid is a chemical compound with formula CHFCOOH. The sodium salt, sodium fluoroacetate, is used as a pesticide. It inhibits the aconitase step of the citric acid cycle. Fluoroacetate occurs naturally in at least 40 plants in Australia, Brazil, and Africa. It is one of only five known organic fluorine-containing natural products. It was first identified in "Dichapetalum cymosum", commonly known as gifblaar (Afrikaans) or poison leaf, by Marais in 1944. As early as 1904, colonists in Sierra Leone used extracts of "Chailletia toxicaria", which also contains fluoroacetic acid or its salts, to poison rats. Several native