Plant stem stems are asparagus, bamboo shoots, cactus pads or nopalitos, kohlrabi, and water chestnut. The spice, cinnamon is bark from a tree trunk. Gum arabic is an important food additive obtained from the trunks of "Acacia senegal" trees. Chicle, the main ingredient in chewing gum, is obtained from trunks of the chicle tree. Medicines obtained from stems include quinine from the bark of cinchona trees, camphor distilled from wood of a tree in the same genus that provides cinnamon, and the muscle relaxant curare from the bark of tropical vines. Wood is used in thousands of ways, e.g. buildings, furniture, boats,
Cinchona "plea for the correct spelling of the genus "Chinchona"". A Spanish physician, Juan Fragoso wrote of bark powder from an unknown tree in 1600 that was used for treating various ills. Nicolas Monardes also wrote of a New World bark powder used in Spain in 1574. Both identify the sources as trees that do not bear fruit and having heart-shaped leaves and it has been suggested that these references could be to "Cinchona" species. The name Quina-Quina or Quinquina was suggested as an old name for Cinchona used in Europe and based on the native name used by the Quechua