YUCCA Yucca This genus includes about thirty species and many varieties. Of the species which grow in the United States, the Tree Yucca or Joshua tree and eight others assume the habit and attain the size of small trees. The Yuccas are among the exceptional Mono cotyledons that increase in diameter through the instrumentality of a cambium layer.' Several of the Yuccas are cultivated because of their beautiful lily-like flowers.
Yucca wood is coarse and fibrous. Direct vertical cleavage is lacking. The fibers interlace so that thin sheets of rotary cut wood can be selected which bend almost as readily as thick felt. Yucca wood is used in special objects such as souvenirs, splints and artificial limbs. Eight species noted by Sudworth are as follows: