One of the first areas you will want to visit in Big Bend is the Dagger Flats Auto Trail. This is a narrow and winding gravel road seven miles long that ends in a "forest" of Yucca faxoniana (syn. =  Y. carnerosana), the Giant Dagger Yucca. One of the major attractions of this route is that you can see a number of the Yucca species in the park in a fairly short period of time, in addition to other interesting plants. You can--and should--pick up a guide published by the Big Bend Natural History Assocation at the beginning of the route. It provides an excellent description of the plants and terrain. This virtual field trip largely follows that guide and you can use it to find all these plants and others on this route.

Agave lechuguilla

A common plant in the Chihuhuan Desert is Agave lechuguilla (Lechuguilla). It is a member of the Agavaceae (Agave Family) and like other members of this family, blooms once after a long period of growth, sets seeds, and dies. The middle image is a flower cluster or inflorescence of Lechuguilla flowers, a spike 2-3 meters long. This plant is eaten by deer. They can't eat the spiny leaves, but rip them off and eat the succulent base of the plant. It is not unusual to find Lechuguilla leaves scattered around where deer have been browsing. You can find this plant in many other areas of the park. The deer was on a trail in the Chisos Mountains.

Larrea tridentata

You will also encounter Larrea tridentata (Creosote bush), another very successful and common desert plant and a member of the Zygophyllaceae or Caltrop family. It has very small, split leaves, yellow flowers and a pubescent (fuzzy) white fruit. It is also aromatic, which indicates the presence of terpenoids (volatile oils). The common name of Creosote bush is due to the smell of these compounds. Terpenoids are long chain hydrocarbons and are found in a large number of plants. They protect the plants from herbivores and, in some cases, prevent other plants from growing in the vicinity (allelopathy). They are probably also the basis for the medicinal use of Creosote bush lotion as an antiseptic. The Creosote bushes you are looking at in the desert may be very old--clones estimated at 11,700 years of age have been found in the Mojave desert.

Fouquieria splendens

Fouquieria splendens (Ocotillo) is one of the more interesting and spectacular plants in Big Bend. It is a member of the Fouquieriaceae or Fouquieria family and is in the only genus in the family. It conserves water by dropping its leaves and going dormant in dry weather. After a rain, Ocotillo produces new leaves. It can serve as an indicator of whether or not an area has recently received rain. The source of much of the rainfall for Big Bend is spotty thunderstorms, so you can see Ocotillo in both dormant and growing states in different areas of the park. The spines are more obvious on the dormant plants.

The plants apparently are not dependent on recent rainfall to flower and fruit. The striking crimson red flowers appear in the spring and the fruits are capsules. The fruits are often bright red and you may mistake them for flowers unless you take a close look.

Echinocereus stramineus

This large clump is Echinocereus stramineus (Strawberry Pitaya), a member of the Cactaceae (Cactus Family). As with most cacti, the leaves have been reduced to spines which function to protect the plant from herbivores. They may also reflect sunlight and radiate heat away from the plant. Unfortunately, we were too early to catch this plant in flower.

Old Ore Road branches off Dagger Flats Road. You should not attempt this drive unless you have a high clearance, preferably 4-wheel drive vehicle and have informed someone that you are going to be travelling on this road. It is a long, hot walk back to the main road.

Diospyros texana

Diospyros texana (Texas Persimmon) occurs in slightly wetter areas, such as the slopes of the dry washes. It is a member of the Ebenaceae (Ebony or Persimmon family). This plant is dioecious, which means that the flowers are unisexual and occur on separate plants. Thus, the plants can be described as either male or female. Obviously, fruits only develop on female plants. The images below are of female flowers and the fruits. The fruits are eaten by wildlife but are incredibly astringent. You will be puckered up for several days, maybe permanently, if you taste one of these when it is unripe. It is better to leave them for the permanent inhabitants of the desert.



Yucca torreyi

Yucca torreyii (Torrey Yucca) is the first species of Yucca that you will encounter on this road. This particular species is the most common one in Big Bend. It is a member of the Agavaceae

Dasylirion leiophyllum

At this point you are about 400 feet higher in elevation than at the beginning of the road, and the vegetation is changing due to the presence of more rainfall at the higher elevations. Dasylirion leiophyllum (Sotol) is found at middle elevations in Big Bend. It is also a member of the Agavaceae. The leaves are used for thatching and baskets and the leaf bases ("spoons") are used in floral arrangements. The trunks are roasted, fermented, and distilled to produce an alcoholic beverage (sotol).

Yucca elata

Yucca elata (Soaptree Yucca) received its common name from a fluid it contains that native Americans used as soap. It is the tallest Yucca in the park. The leaves are narrow relative to those of the other Yuccas.

Juniperus pinchotii

Juniperus pinchotii (Red-berry Juniper) is a plant out of place in this part of park. It is usually found at the wetter, higher elevations. It is a member of the Cupressaceae. It may be a remnant from a time when the climate at Big Bend was moister and cooler. In any case, it is easy to spot. Notice the Yucca growing behind it.

Yucca faxoniana

Yucca faxoniana (Giant Dagger Yucca) is one of the high points (and there are many pointy things in Big Bend) of the Dagger Flats excursion. You will probably have to go to this area to see this particular Yucca because it is rare in the rest of Big Bend. There is a "forest" of these near the turn-around. The plants are very impressive, having large, thick leaves.


Yucca thompsoniana

Yucca thompsoniana (syn. =Y. rostrata) is also found in this area. It has a narrow leaf like Yucca elata (Soaptree Yucca), but the leaf margins of Yucca rostrata are serrated, rather than having the fibers found on Soaptree Yucca.

This is the end of the auto trail. If you visit Big Bend, don't be a weenie, take some time to get out of your car and look around. There is always something interesting going on in the desert that you can't see from a car. Some good advice for looking around the desert: take plenty of water, wear a hat and sunglasses, keep your eyes and ears open (turn off the radio), and don't back up without looking behind you.

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