3. Mexican Pinyon (_Pinus cembroides_), is the only species of pine found along this trail. Pinyon is the name given by the early Spanish explorers and was described by Cabeza de Vaca in 1536. The seeds are used by Indians for food and in recent years the nuts of a close relative, _Pinus edulis_, have become an article of commerce. 4. Gray Oak (_Quercus grisea_). There are several species of oak on this trail, but this particular one is easily recognized by the blue-gray color of its leaves. 5. Emory Oak (_Quercus emoryi_). Of the several oaks in the park, this represents one of the larger evergreen groups. The acorns are edible, sweet, and are important as food for birds and small mammals. Notice the glossy hollylike leaves. 6. Graves Oak (_Quercus gravesi_). Here is another of the oaks with typical notched or toothed leaf margins. The lovely fall colors of the Chisos Mountains (pronounced CHEE-sose) are principally due to the abundance of these trees whose leaves takes on the rusts and reds of autumn. 7. Picture! From this point on the trail there is an excellent view of Green Gulch. The high point on the left (north) of the gulch is Pulliam Peak, 6,921 feet high. The faraway hills are the Rosillos Mountains, so named because of their roan coloring. [Illustration: _Agave_] 8. Agave (_Agave scabra_). There are many different species of agaves (often called century plants) in the Southwest, several occurring in Big Bend. Plants of this group furnish many important products in Mexico, and were utilized by Indians in various ways. Among the products are fiber, food, drink (mescal), soap and medicine. Agaves are grown commercially in more than 40 countries. These plants store up food in the root and leaf systems for many years, finally send up one fast-growing flower stalk, mature their seeds, and then die. The bloom stalk grows almost 10 inches a day and represents the largest bloom of any North American plant. 9. Texas Madrone (_Arbutus texana_). This beautiful tree has thin, peeling bark. Its red berries, which mature in November, are highly favored by deer which often rise up on their hind legs to reach them. The name “Naked Indian” is sometimes applied because the twigs and branches are the copper color of the Indian torso. A close relative of this madrone is found along the west coast. Most of the madrones along this trail were killed by drouth. This one is sprouting from the old base. There are a number of fine living madrones along the road in upper Green Gulch. A fine angle view of Casa Grande is obtainable here. This large single mass of volcanic rock (rhyolite) is 7,300 feet high. 10. Skunkbush Sumac, or Squawbush (_Rhus trilobata_). Although this sumac belongs to the same family as the obnoxious poison ivy, it has none of the latter’s irritating qualities. Leaves turn brilliant shades of red and orange in the autumn.