Page:Popular Science Monthly Volume 75.djvu/451

Rh properties. But this plant is not content with the lowlands, but climbs to the top of the mountain above, where I saw some of the largest of its kind.

Echinocactus ingens, like nearly all of the cacti of this desert, prefers the hills, and there its thick trunk, bristling with long straight spines, grows to a diameter of a barrel and as much as five feet in height. This bears its flowers in a furrow across the top. The pulp of this plant is said by the peons to be sweet, but one who has* tasted other cacti which they eat, may be content to leave the appraisal of this delicacy to others.

The opuntias which cover the plain and mountain are of abundant interest in their variety and numbers. The cylindropuntias abound in forms of cholla, cardencia and tazajillo, according to native terminology, with spines long and sharp and barbed, which penetrate with ease thick leather leggings, and where they stick they stay. In this the tazajillo, which grows as high as a horse's back, is especially to be dreaded, with its stiff slender spines; it separates its joints at a touch and sends them along with the passer-by. Under and around these plants scores of these joints are busy taking root, though one seldom finds thickets of tazajillo. Few of these young plants really have a future before them, though there are enough of them as it is. But the cardencias, arborescent opuntias like the species mammilata, spinosior, etc., of the Arizona desert, are not so savage as the cholla, nor so unexpectedly met with as their more slender and less conspicuous relatives, the tazajillos, as above described. In its varied forms the nopál, or flat-jointed Opuntia, is of more interest to the native than all the other cactus forms. This is about the only kind of cactus that may serve as fodder for cattle, and it is a common sight to behold some hundreds of pounds of one of these species carried on passing ox-carts. At the last camp where these travelers rested one could probably find the remains of a fire where they had burned off the spines of a number of nopals, which indeed is the principal diet of their oxen.

Some of these nopáls are of imposing size and aspect, but mostly they are low procumbent forms, branching out in all directions, pushing forth segment after segment from the lower forward margin of the laterally compressed joint. Along the upper margin occur the flowers and the succession of fruits in varying shades of yellow and red. Here and there at higher altitudes are forms which produce edible fruits not unlike the edible tunas which are produced under cultivation. It seems quite possible that these may be the forerunners of some of the cultivated varieties, inasmuch as the preponderance of evidence points to Mexican origin for the tuna-bearing nopáls. Again we find on the hills a small and compact species which has little to recommend it. This, Opuntia microdasys, has branches closely set with coarse spicules which are easily detached and are said to be a frequent cause of blindness