Yellow and Orange 



prickles like the rose's) ; to cultivate a low habit of growth, not 

 to expose unnecessary surface to sun and air ; to thicken the skin 

 until little moisture could evaporate through the leathery coat; and, 

 finally, to utilize the material thus saved in developing stems so 

 large, fleshy, and juicy that they should become wells in a desert, 

 with powers of sustenance great enough to support the plant 

 through its fiery trials. A common expedient of plants in dry 

 situations, even at the north, is to modify their leaves into spines, 

 as the gorse and the barberry, for example, have done. That such 

 an armor also serves to protect them against the ravages of graz- 

 ing animals is an additional advantage, of course ; but not their 

 sole motive in wearing it. Popular to destruction would the cool 

 juices of the cacti be in thirsty lands, if only they might be 

 obtained without painful and often poisonous scratches. Given 

 moist soil and greater humidity of atmosphere to grow in, spiny 

 plants at once show a tendency to grow taller, to branch and 

 become leafy. A covering of hairs which reflect the light, thus 

 diminishing the amount that might reach the juicy interior area, 

 has likewise been employed by many cacti, among other denizens 

 of dry soil. 



In this common prickly pear cactus of the Atlantic seaboard, 

 where the air is laden with moisture from the ocean, few or no 

 spines are produced ; and dotted over the surface of its branching, 

 fleshy, flattened joints we find tiny, awl-shaped leaves, whereas 

 foliage is entirely wanting in the densely prickly, rounded, solid, 

 unbranched, hairy cacti of the southwestern deserts, and the arid 

 plains of Mexico. 



In sunshine the beautiful yellow blossom of our prickly pear 

 expands to welcome the bees, folding up its petals again for 

 several successive nights. William Hamilton Gibson says it 

 "encloses its buzzing visitor in a golden bower, from which he 

 must emerge at the roof as dusty as a miller," only to enter 

 another blossom and leave some pollen on its numerous stigmas. 



But the cochineal, not the bee, is forever associated with cacti 

 in the popular mind. Indeed, several species are extensively 

 grown on plantations, known as Nopaleries, which furnish food to 

 countless trillions of these tiny insects. Like its relative the aphis 

 of rose bushes (see p. 99), the cochineal fastens itself to a cactus 

 plant by its sucking tube, to live on the juices. The males are 

 winged, and only the female, which yields the valuable dye, sticks 

 tight to the plant. Three crops of insects a year are harvested on a 

 Mexican plantation. After three months' sucking, the females are 

 brushed off, dried in ovens, and sold for about two thousand 

 dollars a ton. The annual yield of Mexico amounting to many 

 thousands of tons, it is no wonder the cactus plant, which fur- 

 nishes so valuable an industry, should appear on the coat-of-arms 

 of the Mexican republic. Some cacti are planted for hedges, the 

 fruit of others furnishes a refreshing drink in tropical climates, 



320 



