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 South America, the species had geographically distinct distributions. The introduction of several species into cultivation in the same areas in India and Java, respectively, by the English and Dutch East India Companies led to the formation of hybrids. Linnaeus described the genus based on the species "Cinchona officinalis." Nearly 300 species have been described and named in the genus but a revision of the genus in 1998 identified 23 distinct species. The febrifugal properties of bark from trees now known to be in the genus "Cinchona" were used by many South American cultures but malaria was an Old World disease