Tree from the cinchona tree ("Cinchona") and was for a long time the remedy of choice for the treatment of malaria. Aspirin was synthesised to replace the sodium salicylate derived from the bark of willow trees ("Salix") which had unpleasant side effects. The anti-cancer drug Paclitaxel is derived from taxol, a substance found in the bark of the Pacific yew ("Taxus brevifolia"). Other tree based drugs come from the paw-paw ("Carica papaya"), the cassia ("Cassia spp."), the cocoa tree ("Theobroma cacao"), the tree of life ("Camptotheca acuminata") and the downy birch ("Betula pubescens"). The papery bark of the white birch tree
Eucalyptus rigidula Eucalyptus rigidula Eucalyptus rigidula, commonly known as stiff-leaved mallee, is a mallee that is native to Western Australia. The mallee typically grows to a height of . The bark of the tree is smooth and white-grey brown in colour and peels in ribbony strips at the base. It blooms between December and April producing inflorescences with white flowers. The bark is smooth and powdery with no pith of bark glands. The disjunct, glossy, green or yellow-green adult leaves have a lanceolate to broad lanceolate shaped blade that is basally tapered. The thick concolorous blade is in length and wide. The