What was the original source of the chemotherapy drug Taxol paclitaxel?

The chemotherapy drug Taxol, or paclitaxel, was originally derived from the bark of the Pacific yew tree (Taxus brevifolia). Discovered in the 1960s, it was found to have significant anti-cancer properties, particularly effective against ovarian and breast cancers. The extraction process from the yew tree was initially complex and unsustainable, leading to the development of semi-synthetic methods for production.