YUCCA. 



(Yucca.) 



The eighteen species constituting this genus are all Ameri- 

 can. Twelve of them are found in the southern and western 

 United States, and eight of these are mentioned by SudwOrth * 

 as arborescent. Several of the Yuccas are cultivated because 

 of their beautiful lily-like flowers. The Tree Yucca or Joshua- 

 tree affords wood. 



This last named species produces a short stout trunk, 

 peculiar in that it is covered by thick bark. The soft, spongy 

 wood is sometimes sawn into lumber, made into souvenirs and 

 lately into artificial limbs. An attempt to manufacture it into 

 paper-pulp t is said to have failed because of high cost made 

 necessary by the remote position of the industry. Hough 

 notes | that trees are sometimes attacked by borers that im- 

 pregnate the walls of their tunnels with hardening antiseptic 

 solutions, causing such parts to remain after the disappearance 

 of the others. And that these parts are described as " petrified 

 wood," and are prized for fuel since they burn with "little 

 smoke and great heat." Yucca wood fibres interlace much as 

 in cloth. The wood has practically no cleavage. This is well 

 shown in pieces that have been steamed and then stretched. 

 Sheets of yucca wood peeled from around the billet (see 

 footnote, page 13) are as roughly pliable as felt of twice the 

 thickness. 



The eight species noted by Sudworth are as follows: 



Yucca arborescens (Joshua tree). Yucca aloifolia ( Aloe-leaf Yucca). 



Yucca treculeana (Spanish Bayonet). Yucca macrocarpa (Breadfruit Yucca). 



Yucca gloriosa (Spanish Dagger). Yucca brevifolia (Schott Yucca). 



Yucca mohavensis (Mohave Yucca). Yucca constricta. 



* "Check List," U. S. Forestry Bui. No. 17. 



f South of Mohave Desert in California about twenty years ago. 



$ American Woods, Part VII, p. 57. 



194 



