Endogenous trees are those that increase from within. Their elemental parts are similar to those of exogenous trees but the arrangement of such parts differs in that the newer fibres of the Endogen intermingle with the old, pass through a pith-like tissue, and cause cross-surfaces to appear as dotted, whereas the new material of the Exogen is deposited altogether and upon the outside of the old, their sections exhibiting rings or layers. The Palms, Yuccas, Cornstalks, and Bamboos are of the endogens. Bark is unusual on trees of the series.
Endogenous woods are hardest and most compact at circumferences. The stems of palm trees are solid, but those of some of the grasses, particularly those that grow quickly, are hollow.[107] The tube or canal, when existing, is due to sluggishness on the part of the central pith, which, developing more slowly than the outer tissues, finally ruptures and disappears at the center. There are also more or less permanent joints or knots,[108] such as are made familiar by the canes and bamboos. The stems of Endogenous plants are seldom cut up into lumber, but are used in segments, or else entire, as for troughs or piles.[109] The use of Palm wood must be more or less [p184] limited to the neighborhoods in which such trees flourish, but it is probable that the Bamboo can be much more generally employed.
The Endogens include numerous families and many thousand species.[110] The grasses, including wheat, rye, and Indian corn at the North and sugar-cane and bamboo at the South, belong to this group. Most Endogens are herbs; comparatively few furnish material for structural purposes. The Palms, including the palmetto, rattans, cane palms, and others, the Yucca, including the Joshua tree, Spanish bayonet, and others, and the Bamboos, representatives of the grasses, are thus useful. Endogens are also known as Monocotyledons. [p185]
PLATE 37. PALM (PalmaceÆ)
| Cabbage Palmetto. (Courtesy N. C. Geological Survey.) | Washington Palm (untrimmed). (Messrs. Doubleday, Page & Co.). | Washington Palm (trimmed). (Los Angeles Chamber Commerce.) |
PALM. PALMACEÆ.
This is one of the largest and most important orders of plants known to man. The one thousand[111] or more known species are distributed over the tropical and semitropical regions of the entire world. Only a few species, including the palmettos of the Gulf States and the fan palms of California are native in the United States.
Palms have tall, columnar trunks without branches, but with crowns of large leaves at their summits. Their forms and proportions are often magnificent. The wood is soft, light, more or less porous, difficult to work, and not strong. The shapes of trunks sometimes cause them to be locally prized for piles, while the porous qualities of the wood are such as to repel teredo.[112] There are many by-products, as fruit, nuts, oil, etc. The rattan or cane palms of India and the Malayan Islands sometimes grow to a height of two hundred feet and are imported into Europe and America for chair-bottoms and the like.
Sudworth[113] enumerates the following as attaining to the dignity of trees in the United States:
- Cabbage Palmetto (Sabal palmetto).
- Silvertop Palmetto (Thrinax microcarpa).
- Silktop Palmetto (Thrinax parviflora).
- Mexican palmetto (Sabal mexicana).
- Sargent Palm (Pseudophoenix sargentii).
- Fanleaf Palm (Washingtonia filifera).
- Royal Palm (Oredoya regia).
[p186]
Cabbage Palmetto. Sabal palmetto Walt.
Nomenclature. (Sudworth.)
Cabbage Palmetto, Palmetto (N. C., S. C.).
Cabbage Tree (Miss., Fla.).
Tree Palmetto (La.).
Locality.
Southern Atlantic and Gulf coast, United States (intermittently).
Features of Tree.
Medium size, thirty to forty feet in height, one to two and one-half feet in diameter.
Color, Appearance, or Grain of Wood.
Light-brown tint. Characteristic coarse fibre arrangement.
Structural Qualities of Wood.
Light, soft, difficult to work; durable in marine work; repels teredo.
Representative Uses of Wood.
Weight of Seasoned Wood in Pounds per Cubic Foot.
Modulus of Elasticity.
Modulus of Rupture.
Remarks.
Scrubbing-brush "bristles" are made in considerable quantities in Florida from the sheath of young leaves. The inner part of young plants is edible. It is said (N. Y. Evening Post, April 20, 1901) that paper is being manufactured from the leaves of the Palmetto. [p187]
Washington Palm. Fanleaf Palm. Washingtonia filifera Wendl. Neowashingtonia filamentosa Wendl.
Nomenclature. (Sudworth.)
Fanleaf Palm, Washington Palm, Desert Palm (Cal.).
California Fan Palm, Arizona Palm, Wild Date (Cal.).
Locality.
Features of Tree.
Thirty to sixty feet in height, one and one-half to three feet in diameter. Fan-shaped leaves rising yet farther in tuft from summit; edible fruit.
Color, Appearance, or Grain of Wood.
Light greenish yellow to dark red, conspicuous grain.
Structural Qualities of Wood.
Soft, light, shrinks in seasoning, difficult to work.
Representative Uses of Wood.
Weight of Seasoned Wood in Pounds per Cubic Foot.
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.
[p189]
PLATE 38. YUCCA (Yucca arborescens).
Top--By courtesy of Messrs. Doubleday, Page & Co. Photograph by Conaway.
Bottom--Wood of Yucca.
Joshua-tree, Yucca. Yucca brevifolia Engel. Yucca arborescens Torr.
Nomenclature. (Sudworth.)
Joshua-tree, The Joshua, Yucca, Yucca Tree (Utah, Ariz., N. M., Cal.).
Yucca Cactus (Cal.).
Locality.
Central and lower Rocky Mountain region.
Features of Tree.
Twenty-five to forty feet in height, six inches to two feet in diameter.
Thick outer cover or bark.[117]
Color, Appearance, or Grain of Wood.
Light brown to white, porous grain.
Structural Qualities of Wood.
Light, soft, spongy, flexible in thin sheets.
Representative Uses of Wood.
Paper-pulp, souvenirs, boxes, book covers, and other small articles.
Weight of Seasoned Wood in Pounds per Cubic Foot.
Modulus of Elasticity.
Modulus of Rupture.
Remarks.
Bark is unusual in the case of endogenous trees. Arborescens refers to fact that it is a tree. [p190]
BAMBOO. (BambusÆ.)
The bamboos are giant members of a group (grasses[118]), the other individuals of which, while widely distributed, valued, and very numerous, are for the most part insignificant as to bulk, height, and structural characteristics. The canes and bamboos are exceptions in that they form what may well be called forests, and produce woods used in construction. The Bamboos (BambusÆ), including about twenty genera and two hundred species,[119] are distributed unevenly over the tropical zone.
PLATE 39. BAMBOO (BambusÆ).
Top--Bamboo Grove, Philippines.
By the courtesy of the Manila P.O. Forestry Bureau.
Bottom--Bamboo Grove, China.
Bamboo sections, 5-1/4 inches diameter.
The bamboo plant with its numerous stalks and delicate foliage resembles a plume of giant ostrich feathers. The stems attain heights of seventy feet and diameters of four and six inches (see Fig. 3 plate). Knots or joints are at first close together, but are later one or two feet apart. Growth is surprisingly rapid. A Philippine specimen, which when measured was eighteen inches high and four inches in diameter, grew two feet in three days.[120] Florida stalks have reached heights of seventy-two feet in a single season.[121] The plants are apt to take complete possession of the ground on which they grow. Those who use bamboo value it highly. It is employed entire or else split into segments. Some can be [p191] opened and flattened into rough boards, splitting everywhere but holding together.[122] For vessels it is cut off with reference to the partitions. The subject is thus summarized by Dr. Martin:[123] "The Chinese make masts of it for their small junks, and twist it into cables for their larger ones. They weave it into matting for floors, and make it into rafters for roofs. They sit at table on bamboo chairs, eat shoots of bamboo with bamboo chop-sticks. The musician blows a bamboo flute, and the watchman beats a bamboo rattle. Criminals are confined in a bamboo cage and beaten with bamboo rods. Paper is made of bamboo fibre, and pencils of a joint of bamboo in which is inserted a tuft of goat's hair."
The manipulation of this valuable material is not yet understood in America. Prof. Johnson notes[124] that the wood of "bamboo is just twice as strong as the strongest wood in cross-bending, weight for weight, when the wood is taken in specimens, with a square and solid cross-section." Dr. Fernow considers the bamboo worthy of extensive trial throughout the Gulf region.[125] [p192]
Bamboo. Bambusa vulgaris.
Nomenclature.
Bamboo local and common name.
Locality.
Features of Tree.
Seventy-five feet in height, four to six inches in diameter. Delicate branches and leaves. Greenish glazed jointed stem, extensive roots.
Color, Appearance, or Grain of Wood.
Yellowish brown, conspicuously fibrous, moderately thin walls, central canal broken by joints.
Structural Qualities of Wood.
Light, elastic, works easily.
Representative Uses of Wood.
Posts, poles, utensils, troughs, pipes, roofing, paper.
Weight of Seasoned Wood in Pounds per Cubic Foot.
Modulus of Elasticity.
2,380,000 (Johnson's "Materials of Construction," p. 689).
Modulus of Rupture.
27,400 (Johnson's "Materials of Construction," p. 689).
Remarks.
