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
Chrysolepis three sweet, edible nuts, eaten by the indigenous peoples. The fruit also provides food for birds and wildlife. "Chrysolepis" is related to the subtropical southeast Asian genus "Castanopsis" (in which it was formerly included), but differs in the nuts being triangular and fully enclosed in a sectioned cupule, and in having bisexual catkins. "Chrysolepis" also differs from another allied genus "Castanea" (chestnuts), in nuts that take 14–16 months to mature (3–5 months in "Castanea"), evergreen leaves and the shoots having a terminal bud. There are two species of "Chrysolepis" — "Chrysolepis chrysophylla" and "Chrysolepis sempervirens" — which like many species