This document describes the distinguishing features of several tree types. Pines have long thin needles, hemlocks have very short flat needles, and fir trees have single needles that grow directly on twigs without stalks. Oaks produce acorns, elm trees produce small flat seeds, and maple trees produce paired seeds called keys. The raffia palm has the largest leaves in the world at 65 feet long, while coconut palms are among the most useful with their fruit, and date palms are known for their delicious dates. Two native American palm varieties are the sabal palm and Washington palm.