Popular Science Monthly/Volume 51/September 1897/The Giant Cactus

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PEOPLE in general are but little impressed by the many forms of life, be they plant or animal, with which they daily come in contact. A tree of unusual size, or a flower of exceptional form or color, attracts our attention. It is the unusual in Nature which always catches the eye. The New England boy grows to manhood under the widespreading boughs of the American elm, in sight of grass-covered mountains and winding rivers. The natural beauty of his surroundings is a part of himself. So, also, the Papago Indian sees nothing peculiar in the many forms of life characteristic of the region where he makes his home.

He can not listen to the whispering of the leaves, because the trees of his limited world do not grow them. He knows nothing of tangled woods, but draws his inspiration from the broad, hot, cactus-covered plains and the granite-walled and lava-strewn mountains.

The many and varied species of cacti, which constitute the vegetation most familiar to him, are the most peculiar of all forms of vegetable life to those who live beyond the limits of our arid region. Of all these strange plants the sahuaro, or giant cactus, on account of its great size and striking aspect, is the most impressive. We can well imagine the feeling of the early explorers when they first came in sight of these towering plants, so abundant on the foothills contiguous to Salt River Valley, and from where they extend southward far into Mexico. The finest and largest specimens that I have ever observed are growing only a few miles from Tucson, on the foothills of the Santa Catalina Mountains, where hundreds may be seen growing on a single acre, many extending their huge green columns to the height of fifty feet. The many ribs which parallel the columns are surmounted by bunches of heavy spines. With great age the spines fall away from the lower portion of the plant, leaving the broad, obtuse ribs devoid of their natural protector. This fact led the first observers to report the plant spineless.

When lighted, the spines burn readily; the flame, soon ascending, burning the spines in its path until it reaches the top. From this fact the plant is sometimes recognized as the "Arizona candle."

Just beneath the epidermis and alternating with the spiny ribs are strong ligneous fascicles. These fascicles are of the same number as the ribs, and serve as a support for the soft parenchyma tissue which constitutes the great bulk of the plant.

The fascicles are not unlike huge fish poles, twenty to forty feet long and from one to three inches in diameter, flattened radially as relates to their position of growth. This woody portion endures long after the other parts of the plant have decayed and is popularly known as the skeleton. During the growth of

PSM V51 D658 A cactus forest.jpg

A Cactus Forest.

the plant the fascicles increase in size each year by the addition of a woody layer to their outer surface, in the same manner as the oak and maple add their annual layers. The layers of growth forming the older fascicles are very close together, sometimes a hundred being crowded into less than an inch of space.

This portion of the plant is of great value to both Indians and Mexicans, as it not only serves as firewood but is extensively utilized in both fence and house building. When cut to requisite length it makes excellent pickets, and throughout its entire range the dirt roofs of the adobe houses are supported by the long, strong fascicles.

We find by counting the layers of growth that many of the older plants have been more than a century and a half in growing. The size of the plant is not always a fair criterion of its PSM V51 D659 Giant cactus cereus giganteus.jpgGiant Cactus (Cereus giganteus). (Engelm.) age, as plants eight to ten feet high, growing from the granite rocks on the southern slopes of the Santa Catalina Mountains, are older than plants four or five times larger growing in deep canons or in yards about the city, where the water supply is not so completely withdrawn. The ability, however, of this plant to withstand prolonged drought is very great. Its enormous mass of succulent tissue, protected by a thick epidermis, enables it to maintain the accumulated moisture for an almost indefinite period, even after every source of outside moisture has been dried up. A plant may be taken up, exposed to the hot, dry air for months, and when replaced in the soil continue to grow, having suffered little apparent injury. Living specimens, weighing several hundred pounds, may be packed in boxes and shipped to Europe and other foreign countries, without injury to their vitality. A few years ago a specimen some eight feet high was placed in the window of one of the Tucson shops. Some eighteen months later it was found on examination to still contain a large amount of moisture. Its vitality is further illustrated by the fact that a foot or more of the top may be cut from the plant in early spring and sent across the continent, flowers developing on the detached portion several weeks after it has reached its destination.

A number of birds, including the Gila woodpecker, the red shafted flicker, and the golden flicker, excavate great holes in the soft tissues in which they build their nests. Later the abandoned houses of the woodpeckers are favorite retreats for the Mexican screech owl and the pygmy owl. An occasional bat, overtaken by sunlight, passes the day in one of these dark holes, and when the excavation extends through, from side to side, the cactus wren brings in its miscellaneous collection of sticks and straws and makes itself at home.

The first flowers appear when the plant reaches a height from eight to twelve feet, and at this time branches develop; usually forming a whorl a few feet below the summit. In the course of a year or two the branches assume an upright position, forming columns parallel to the main stem.

The large, waxy-white flowers are borne in the axils of the bunches of spines, at or a few inches below the summit of the trunk and branches; sometimes a half hundred crowning the summit of a single branch. They begin to bloom during the early days of May, and are not entirely gone before the middle of June. By midsummer the thick stems are loaded with ripened fruit, and the harvest time for both birds and Indians is at hand. The latter, mounted on ponies, pass from tree to tree, armed with long poles, with which they detach the fruit and bring it to the ground. The squaws gather it in baskets and carry it to their village, where it constitutes the staple article of food for the time being. The surplus is made into a preserve having the consistence of thick molasses, and is nearly as sweet. It is then packed in small ollas and put away for future use. Not always, however, is the surplus fruit put to this use, but instead is made into a rank, intoxicating drink.

The fresh fruit is not unpleasant, even to the cultivated palate, and is very unlike the slimy, mucilaginous fruits of many other species. At maturity they are fully three inches long and half as wide. In a few days the pericarp, or thick outer rind, splits at the summit into several segments, which, curling back, exposes the rich, red pulpy interior. The segments spreading in all directions appear from a distance like gayly colored petals. As they become more deflexed the central portion falls to the ground, leaving only the pericarp attached to the plant. The edible portion consists of the long, fleshy funiculi which attach the numerous small black seeds to the ovary.

Nearly a half hundred birds feed upon the rich, nutritious fruit of this plant, the list including all our thrashers, wood-peckers, finches, and pigeons. It is through the agency of these birds that the seeds become disseminated.