32.
Modulus of Elasticity.
Modulus of Rupture.
Remarks.
The largest of the United States Palms. Much used for landscape effects in California. [p188]
YUCCA. (Yucca.)
The eighteen species constituting this genus are all American. Twelve of them are found in the southern and western United States, and eight of these are mentioned by Sudworth[114] 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[115] is said to have failed because of high cost made necessary by the remote position of the industry. Hough notes[116] that trees are sometimes attacked by borers that impregnate 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."
The eight species noted by Sudworth are as follows:
- Yucca arborescens (Joshua tree).
- Yucca treculeana (Spanish Bayonet).
- Yucca gloriosa (Spanish Dagger).
- Yucca mohavensis (Mohave Yucca).
- Yucca aloifolia (Aloë-leaf Yucca).
- Yucca macrocarpa (Broadfruit Yucca).
- Yucca brevifolia (Schott Yucca).
- Yucca constricta.