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
Terminalia sericea to tall. The bark is a reddish or greyish brown colour and peels away in strips. The bluish-green leaves tend to be clustered at the tips of the branches. They are ovate with entire margins and both the upper and lower surfaces are clothed in silvery hairs. The flowers are white and are borne in short axilliary spikes. They have an unpleasant smell and may be pollinated by flies. The fruit are winged nuts containing a single seed and turn a darker pink colour as they ripen. They may remain attached to the branch for a year and are dispersed