This annual thrives in waste places and often spreads along walks and driveways where it is difficult for other vegetation to grow. Pineappleweed is named for a very pleasant "pineapple-like" aroma, which results when its leaves are crushed. Leaves of pineappleweed are very delicate and finely divided. Flowers aare yellow-green and lack marginal, or ray petals. Pineappleweed is believed to have originated in the Western states and then spread its way across northern areas of the continent. It is often confused with mayweed, or dog fennel, which has a very offensive odor.