The fruits, which are produced in quantities, are armed with strong spurs which become embedded in the feet and fur of animals and in automobile tires. Fruits are also carried by irrigation or flood waters. Although the spurs are too short to puncture automobile tires, they make bicycles almost useless in some localities, and are an aggravation to children who go barefoot—and to dogs. Flowers and fruits in various stages of maturity may be found on this fast-growing plant at almost any time during the summer months. Botanically, Puncturevine is closely related to the Creosotebush and also to the Arizona-poppy. YELLOW [Illustration: Kallstroemia grandiflora] Common names: ARIZONA-POPPY, CALTROP Arizona and Texas deserts: (_Kallstroemia grandiflora_). Bright yellow. February-September. Caltrop family. Size: 1 to 2 feet tall. Although superficially resembling in size, shape, and color the blossoms of the Goldpoppy, the blossoms of the large-flowered Caltrop have five petals instead of four, and the plant is a close relative of the Puncturevine and the Creosotebush. One of the most attractive of the desert’s summer annuals, Arizona-poppy is found at elevations below 5,000 feet in the drylands of Texas, New Mexico, Arizona, and northern Mexico. Large-flowered Caltrop may be distinguished from Goldpoppy by (1) sprawling open habit of growth, (2) compound leaves, (3) season of blossoming, and (4) the fact that the plants grow singly rather than in masses. YELLOW [Illustration: Larrea tridentata] Common names: GREASEWOOD, CREOSOTEBUSH, (_HEDIONDILLA_) Arizona, California, and Texas deserts: (_Larrea tridentata_). Yellow. Spring. Caltrop family. Size: Shrub, 2 to 8 feet high. No one could justifiably question the statement that Creosotebush is the most successful, widespread, and readily recognized desert plant of the hot, arid regions of North America. It often occurs over wide areas in such pure stands as to constitute true _Larrea_ plains. Its common companion is the grayish Burrobush or Bur-sage. Following winter rains, the Creosotebush may put out a few yellow blossoms in January, but usually bursts into full flower in April or May, to be followed in a short time with the equally spectacular fuzzy white seed balls making the bushes appear to be covered with a light frosting of snow. After a rain, the plants give off a musty, resinous odor which is the basis of the Mexican name _Hediondilla_ (freely translated, “Little Stinker”). Lac occurs as a resinous incrustation on the branches, and was used by the Indians for mending pottery, making mosaics, and for fixing arrow points.